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Sample records for owls bubo bubo

  1. Non-territorial floaters in Great Horned Owls (Bubo virginianus)

    Treesearch

    Christoph Rohner

    1997-01-01

    The ecology and behavior of non-territorial owls are basically unknown. I studied the integration of young Great Horned Owls (Bubo virginianus) into the territorial breeding population from 1988-1993 in the southwestern Yukon, Canada, during a peak and decline of the population cycle of snowshoe hares (Lepus americanus). Fifty-five...

  2. Synovial chondromatosis in a great horned owl (Bubo virginianus).

    PubMed

    Howard, M O; Nieves, M A; Miles, K G

    1996-04-01

    A case of synovial chondromatosis in a great horned owl (Bubo virginianus) was found in June 1993. In radiographs of bilateral swelling of the scapulohumeral joint we observed numerous mineralized foci in the soft tissue. The foci were identified by light microscopy as cartilaginous metaplasia. This is the first report of synovial chondromatosis in an owl.

  3. Factors influencing territorial occupancy and reproductive success in a Eurasian Eagle-owl (Bubo bubo) population.

    PubMed

    León-Ortega, Mario; Jiménez-Franco, María V; Martínez, José E; Calvo, José F

    2017-01-01

    Modelling territorial occupancy and reproductive success is a key issue for better understanding the population dynamics of territorial species. This study aimed to investigate these ecological processes in a Eurasian Eagle-owl (Bubo bubo) population in south-eastern Spain during a seven-year period. A multi-season, multi-state modelling approach was followed to estimate the probabilities of occupancy and reproductive success in relation to previous state, time and habitat covariates, and accounting for imperfect detection. The best estimated models showed past breeding success in the territories to be the most important factor determining a high probability of reoccupation and reproductive success in the following year. In addition, alternative occupancy models suggested the positive influence of crops on the probability of territory occupation. By contrast, the best reproductive model revealed strong interannual variations in the rates of breeding success, which may be related to changes in the abundance of the European Rabbit, the main prey of the Eurasian Eagle-owl. Our models also estimated the probabilities of detecting the presence of owls in a given territory and the probability of detecting evidence of successful reproduction. Estimated detection probabilities were high throughout the breeding season, decreasing in time for unsuccessful breeders but increasing for successful breeders. The probability of detecting reproductive success increased with time, being close to one in the last survey. These results suggest that reproduction failure in the early stages of the breeding season is a determinant factor in the probability of detecting occupancy and reproductive success.

  4. Factors that influence mercury concentrations in nestling Eagle Owls (Bubo bubo).

    PubMed

    Espín, Silvia; Martínez-López, Emma; León-Ortega, Mario; Calvo, José F; García-Fernández, Antonio Juan

    2014-02-01

    Mercury (Hg) is a global pollutant that bioaccumulates and biomagnifies in food chains, and is associated with adverse effects in both humans and wildlife. The Hg levels detected in blood obtained from Eagle Owl (Bubo bubo) chicks in Southeast Spain (Murcia) can be considered low (mean Hg concentration in blood from 2006 to 2012 was 36.83 ± 145.58 μg/l wet weigh, n=600), and it is therefore unlikely that Hg pollution can negatively affect their breeding. Positive correlation (r=0.339, p<0.001, n=229) was found to exist between the Hg concentrations in the blood and back feathers of the chicks. We provide a regression equation that could be helpful to estimate blood Hg levels when analyzing Hg concentrations in back feathers. Blood Hg concentrations in Eagle Owls have shown positive correlations with Hg levels in rabbit muscles, more evident in nests from the Northern area (r=0.600, p=0.014, n=16), where rabbits are the main prey of Eagle Owls. The best Linear Mixed Model to explain variations in blood Hg concentrations in nestling Eagle Owls includes year and location within the mining area as variables. The variable year is assigned the largest value of relative importance, followed by the location in the ancient mining sites and then the zone. Rainfalls may have an effect on the temporal differences in the blood Hg concentrations of nestling Eagle Owls. Although the studied region is not considered Hg polluted, the Hg levels were higher in Eagle Owls and European Rabbits from areas within the ancient mining sites as compared to those in the entire region. This result shows that spatial differences in Hg concentrations in Eagle Owls may be affected by local contamination, and that the role of diet composition may be less significant.

  5. The Macroanatomy of the Sacral Plexus and Its Nerves in Eurasian Eagle Owls (Bubo bubo).

    PubMed

    Akbulut, Y; Demiraslan, Y; Aslan, K; Coban, A

    2016-10-01

    This study was carried out to reveal the formation of the sacral plexus in the Eurasian Eagle Owls (Bubo bubo) and the nerves originating from this plexus. Five EEOs, three of them were male and two were female, were provided from Wildlife Rescue and Rehabilitation Center of Kafkas University and used as materials. Following the euthanizing of the animals, abdominal cavity was opened. The nerves of plexus sacrales were dissected and photographed. It was detected that the sacral plexus was formed by the ventral ramus of five synsacral nerves. Moreover, it was determined that the roots of the sacral plexus formed three trunks: the truncus cranialis, the truncus medius and the truncus caudalis in fossa renalis. The availability of the n. ischiofemoralis and the availability of n. parafibularis were detected in the EEOs. Five branches were specified as having segregated from the sacral plexus: the n. cutaneus femoralis caudalis, the mutual root of n. fibularis with n. tibialis (n. ischiadicus), the rami musculares, the n. coxalis caudalis and the ramus muscularis. It was observed that the sacral plexus was linked to the lumbar plexus by the n. furcalis, to the pudendus plexus via the n. bigeminus. Consequently, the anatomic structure of the EEO's sacral plexus, the participating synsacral nerves to plexus and the innervation areas of these nerves were revealed. © 2015 Blackwell Verlag GmbH.

  6. Factors influencing territorial occupancy and reproductive success in a Eurasian Eagle-owl (Bubo bubo) population

    PubMed Central

    León-Ortega, Mario; Jiménez-Franco, María V.; Martínez, José E.

    2017-01-01

    Modelling territorial occupancy and reproductive success is a key issue for better understanding the population dynamics of territorial species. This study aimed to investigate these ecological processes in a Eurasian Eagle-owl (Bubo bubo) population in south-eastern Spain during a seven-year period. A multi-season, multi-state modelling approach was followed to estimate the probabilities of occupancy and reproductive success in relation to previous state, time and habitat covariates, and accounting for imperfect detection. The best estimated models showed past breeding success in the territories to be the most important factor determining a high probability of reoccupation and reproductive success in the following year. In addition, alternative occupancy models suggested the positive influence of crops on the probability of territory occupation. By contrast, the best reproductive model revealed strong interannual variations in the rates of breeding success, which may be related to changes in the abundance of the European Rabbit, the main prey of the Eurasian Eagle-owl. Our models also estimated the probabilities of detecting the presence of owls in a given territory and the probability of detecting evidence of successful reproduction. Estimated detection probabilities were high throughout the breeding season, decreasing in time for unsuccessful breeders but increasing for successful breeders. The probability of detecting reproductive success increased with time, being close to one in the last survey. These results suggest that reproduction failure in the early stages of the breeding season is a determinant factor in the probability of detecting occupancy and reproductive success. PMID:28399175

  7. Complete mitochondrial genome of Eagle Owl (Bubo bubo, Strigiformes; Strigidae) from China.

    PubMed

    Hengjiu, Tian; Jianwei, Ji; Shi, Yang; Zhiming, Zhang; Laghari, Muhammad Younis; Narejo, Naeem Tariq; Lashari, Punhal

    2016-01-01

    In the present study, the complete mitochondrial genome sequence of Bubo bubo using PCR amplification, sequencing and assembling has been obtained for the first time. The total length of the mitochondrial genome was 16,250  bp, with the base composition of 29.88% A, 34.16% C, 14.35% G, and 21.58% T. It contained 37 genes (2 ribosomal RNA genes, 13 protein-coding genes and 22 transfer RNA genes) and a major non-coding control region (D-loop region). The complete mitochondrial genome sequence of Bubo bubo provides an important data set for further investigation on the phylogenetic relationships within Strigiformes.

  8. Pulmonary carcinoma in a great horned owl (Bubo virginianus).

    PubMed

    Rettenmund, Christy; Sladky, Kurt K; Rodriguez, Daniel; Petersen, Michael; Pinkerton, Marie E; Rao, Deepa

    2010-03-01

    Pulmonary carcinoma was diagnosed in an 18+-year-old captive female great horned owl (Bubo virginianus). The owl presented with a history of progressive weakness and sudden onset of frank blood in the droppings. On physical examination, the owl had multiple white to yellow plaques in the oral cavity, decreased air sac sounds on the right side, dyspnea (during manual restraint), and reduced pectoral musculature. Whole-body radiographs revealed obliteration of the right-sided air sacs, a soft tissue plaque/density in the left caudal thoracic air sac, soft tissue opacity over the coelomic organs, and increased medullary opacity in the distal right humerus. The owl died during anesthetic recovery, and the body was submitted for necropsy. Although the clinical signs, physical examination results, radiographic signs, and gross pathology supported a diagnosis of mycotic infection, such as aspergillosis, histopathology confirmed pulmonary carcinoma with metastases to the air sacs and humerus.

  9. A curious pellet from a great horned owl (Bubo virginianus)

    USGS Publications Warehouse

    Woodman, N.; Dove, C.J.; Peurach, S.C.

    2005-01-01

    One of the traditional methods of determining the dietary preferences of owls relies upon the identification of bony remains of prey contained in regurgitated pellets. Discovery of a pellet containing a large, complete primary feather from an adult, male Ring-necked Pheasant (Phasianus colchicus) prompted us to examine in detail a small sample of pellets from a Great Horned Owl (Bubo virginianus). Our analyses of feather and hair remains in these pellets documented the presence of three species of birds and two species of mammals, whereas bones in the pellets represented only mammals. This finding indicates an important bias that challenges the reliability of owl pellet studies making use of only osteological remains.

  10. Presumptive electric cataracts in a Great Horned owl (Bubo virginianus).

    PubMed

    Dees, D Dustin; MacLaren, Nicole E

    2013-01-01

    This case report describes suspected electrocution in a juvenile female Great Horned owl (Bubo virginianus) with subsequent bilateral cataract formation. The bird flew into a high-voltage power line and was immediately rescued. Burn wounds of the head and ataxia with apparent blindness were noted. Initial ophthalmic examination 5 days after the incident revealed bilaterally symmetrical anterior subcapsular vacuolar cataracts with absence of intraocular inflammation and a predominantly clear view to the normal appearing fundus. The bird appeared to be nonvisual. No ophthalmic medications were prescribed at initial examination. Subsequent recheck examination at 8 weeks revealed moderate resolution of the cataracts and improved vision. To the authors' knowledge, this is the first published report of suspected electric cataracts in an avian species. © 2012 American College of Veterinary Ophthalmologists.

  11. [Successful rehabilitation and release with a subsequent brood of a one-eyed eagle owl (Bubo bubo)].

    PubMed

    Hegemann, Arne; Hegemann, Ernst Dieter; Krone, Oliver

    2007-01-01

    The rehabilitation and release of injured or ill raptors and owls is widespread. The overall aim of this intervention is the successful reintroduction of the bird into the wild population. Though many injuries are treatable, it is thought that vision-impaired birds have no change of survival and their release is refused. Here we report a case study and give a description of the rehabilitation and subsequent release of an injured Eagle Owl (Bubo bubo). The bird was found with an injured eye and a paralysed wing in the district of Soest, North Rhine-Westphalia, Germany. While the paralysis healed, the bird stayed blind in one eye. Nevertheless it was released with a radio-transmitter. The female Eagle Owl could be followed by radio-telemetry for more than half a year after release, by visual and acoustic skills for a full year after release. Although the female was only two years old, it paired successful with a partner, and raised a brood with three offspring. No differences in the behaviour compared to non-handicapped birds could be detected. This one-eyed Eagle Owl demonstrates not only survival, but also successful reproduction following reintegration into the wild population. However, low intraspecific competition in the area might have contributed to the reproductive success of the owl.

  12. Presumptive keratoglobus in a great horned owl (Bubo virginianus).

    PubMed

    Lau, Rachael K; Moresco, Anneke; Woods, Sarah J; Reilly, Christopher M; Hawkins, Michelle G; Murphy, Christopher J; Hollingsworth, Steven R; Hacker, Dennis; Freeman, Kate S

    2016-07-31

    A juvenile to young adult, male, great horned owl (Bubo virginianus,GHOW) was presented to the wildlife rehabilitation hospital at Lindsay Wildlife Museum (WRHLWM) due to trauma to the right patagium from barbed wire entanglement. On presentation, both corneas were irregular, dry, and no movement of the third eyelid was noted. A severe corneal enlargement/globoid appearance was the predominant ophthalmic feature. The fundus was normal in both eyes (OU). Over the course of several days, both corneas developed edema combined with further dessication at the ocular surface associated with diffuse dorsal fluorescein stain uptake. Repeated ophthalmic examinations found normal intraocular pressures and an inability to move the third eyelid over the enlarged corneas. The bird was deemed nonreleasable due to severe wing damage and poor prognosis associated with eye abnormalities and was humanely euthanized. Postmortem CT, enucleation, and histopathology were performed to evaluate the ocular anatomical abnormality and confirm the suspected diagnosis of keratoglobus. This GHOW represents the first reported case of presumptive keratoglobus in a raptor. © 2016 American College of Veterinary Ophthalmologists.

  13. Chronic myelogenous leukemia in a great horned owl (Bubo virginianus).

    PubMed

    Wiley, Jennifer L; Whittington, Julia K; Wilmes, Christine M; Messick, Joanne B

    2009-03-01

    A free-ranging adult female great horned owl (Bubo virginianus) was presented to the Wildlife Medical Clinic at the University of Illinois after being observed with anorexia and decreased activity. A severe leukocytosis (212 400 cells/microl), primarily comprised of mature heterophils, was found at presentation. Results of various diagnostic tests including radiographs, Chlamydophila serologic testing, measurement of Aspergillus antibody and antigen titers, plasma protein electrophoresis, fecal culture and acid-fast staining, coelioscopy, endoscopy, tracheoscopy, exploratory coelomotomy, nuclear scintigraphy, tissue cultures, bone marrow biopsy, and histopathology revealed no underlying cause for the persistent leukocytosis. No response to treatment with antibiotics or antifungal agents was observed, although a transient, significant decrease in the leukocyte count (6200 cells/microl) was observed after treatment with fenbendazole. A presumptive diagnosis of chronic myelogenous leukemia was made based on 3 factors: disease duration of greater than 3 months, a lack of identifiable foci of inflammation, and a lack of response to conventional therapy. The diagnosis was confirmed based on postmortem examination and testing 177 days after initial presentation.

  14. Great Horned Owl (Bubo virginianus) productivity and home range characteristics in a shortgrass prairie

    Treesearch

    Rosemary A. Frank; R. Scott Lutz

    1997-01-01

    We studied movements and breeding success of resident Great Horned Owls (Bubo virginianus) at the Rocky Mountain Arsenal National Wildlife Refuge from 1994-1996. We captured adult owls prior to nest initiation and outfitted them with radio transmitters. Twelve, 5, and 11 pairs nested each year, respectively. Eleven nests successfully hatched and...

  15. Knemidokoptes mutans (Acari: Knemidocoptidae) in a great-horned owl (Bubo virginianus).

    PubMed

    Schulz, T A; Stewart, J S; Fowler, M E

    1989-07-01

    A routine examination of a captive juvenile great-horned owl (Bubo virginianus) revealed bilateral proliferative papillary hyperkeratosis on the feet. Microscopic examination of skin scrapings produced numerous mites identified as Knemidokoptes mutans. This is the first record of this parasite in a great-horned owl. A single dose of ivermectin (200 micrograms/kg) was effective in treatment of this infection.

  16. Glaucoma in a captive-bred great horned owl (Bubo virginianus virginianus).

    PubMed

    Rayment, L J; Williams, D

    1997-05-03

    A captive-bred adult great horned owl (Bubo virginianus virginianus) behaved as though it was bilaterally blind. An ophthalmological examination showed that it had an increased intraocular pressure in both eyes and gonioscopy showed an abnormality of the iridocorneal angles. Retinal changes were also observed. Treatment was not attempted and the owl was euthanased. Histopathology confirmed the abnormal iridocorneal angles, but the exact aetiology of the primary glaucoma was not identified.

  17. Oxidative stress biomarkers in Eurasian eagle owls (Bubo bubo) in three different scenarios of heavy metal exposure.

    PubMed

    Espín, Silvia; Martínez-López, Emma; León-Ortega, Mario; Martínez, José Enrique; García-Fernández, Antonio Juan

    2014-05-01

    The main aim of the present study is the assessment of oxidative stress related to metals in the Eurasian eagle owl (Bubo bubo) from three areas (agricultural and rural area, industrial area, and mining area) of Murcia, Southern Spain. Mean blood metal concentrations were Cd=0.07±0.21, Pb=3.27±5.21, Cu=10.62±4.77, Zn=311.47±67.14, Hg=2.32±3.83 μg/dl wet weight. Although individuals from the mining area had significant higher Pb and Hg concentrations, and significant lower glutathione-S-transferase (GST) and catalase (CAT) activities in red blood cells (RBC); the lack of differences in oxidative damage to membrane lipids (TBARS) among areas suggests that the antioxidant capacity of the different populations is able to deal with oxidant species and maintain TBARS levels in the same amount. Despite the low levels of metals, several oxidative stress biomarkers were correlated with metal concentrations. This study provides threshold concentrations at which metals cause effects on the antioxidant system in Eagle owls. Blood Cd concentrations greater than 0.3 μg/dl produced an inhibition in GPx (32%) and CAT (26%) activity in RBC. However, Cd concentrations higher than 0.02 μg/dl were enough to produce an inhibition of these enzymes. Regarding Pb levels, blood concentrations above 2 μg/dl produced an inhibition of 8% and 10.5% in GPx and CAT activities, respectively, in RBC. A depletion of 16% and 4% in tGSH levels was associated with Pb concentrations higher than 15 and 3 μg/dl, respectively, in individuals from the ancient mine site. In addition, Pb concentrations above 2 and 10 μg/dl produced a TBARS induction of 10% and 28%, respectively, in individuals from both the industrial and the mining area. Finally, Hg concentrations greater than 3 and 10 μg/dl resulted in a TBARS induction of 102% and 190%, respectively, in Eurasian eagle owls from the industrial area. Our findings show that Pb may produce effects on oxidative stress biomarkers in Strigiformes at

  18. Disseminated lymphoma of presumptive T-cell origin in a great horned owl (Bubo virginianus).

    PubMed

    Malka, Shachar; Crabbs, Torrie; Mitchell, Elizabeth B; Zehnder, Ashley; Kent, Michael S; Lowenstine, Linda J; Hawkins, Michelle G

    2008-09-01

    A geriatric male great horned owl (Bubo virginianus) that was a resident at a raptor center was presented for examination because of stridor and weight loss. Results of physical examination, diagnostic imaging, and biopsy were consistent with disseminated lymphoma involving the oropharynx, neck region (including thyroid and parathyroid glands), keel, spleen, and liver. Attempts to treat the owl with chlorambucil failed, and the owl was euthanatized 5 months later. Neoplastic cells from this owl were immunoreactive to CD-3 antibody, suggesting the lymphoma was of T-cell origin.

  19. Columbid herpesvirus-1 mortality in great horned owls (Bubo virginianus) from Calgary, Alberta

    PubMed Central

    Rose, Nicole; Warren, Amy L.; Whiteside, Douglas; Bidulka, Julie; Robinson, John H.; Illanes, Oscar; Brookfield, Caroline

    2012-01-01

    Four cases of Columbid herpesvirus-1 infection in great horned owls (Bubo virginianus) were identified in Calgary, Alberta. Necropsy findings included severe multifocal hepatic and splenic necrosis, pharyngeal ulceration and necrosis, and gastrointestinal necrosis. Occasional eosinophilic intranuclear viral inclusion bodies were associated with the foci of necrosis and polymerase chain reaction (PCR) testing confirmed a diagnosis of herpesvirus-induced disease. The sequence of a PCR amplicon had 99.7% homology to Columbid herpesvirus-1. PMID:22942441

  20. Columbid herpesvirus-1 mortality in great horned owls (Bubo virginianus) from Calgary, Alberta.

    PubMed

    Rose, Nicole; Warren, Amy L; Whiteside, Douglas; Bidulka, Julie; Robinson, John H; Illanes, Oscar; Brookfield, Caroline

    2012-03-01

    Four cases of Columbid herpesvirus-1 infection in great horned owls (Bubo virginianus) were identified in Calgary, Alberta. Necropsy findings included severe multifocal hepatic and splenic necrosis, pharyngeal ulceration and necrosis, and gastrointestinal necrosis. Occasional eosinophilic intranuclear viral inclusion bodies were associated with the foci of necrosis and polymerase chain reaction (PCR) testing confirmed a diagnosis of herpesvirus-induced disease. The sequence of a PCR amplicon had 99.7% homology to Columbid herpesvirus-1.

  1. Importance of prairie wetlands and avian prey to breeding Great Horned Owls (Bubo virginianus) in Northwestern North Dakota

    Treesearch

    Richard K. Murphy

    1997-01-01

    Prey use by Great Horned Owls (Bubo virginianus) is documented widely in North America, but not in the vast northern Great Plains. During spring through early summer 1986-1987, I recorded 2,900 prey items at 22 Great Horned Owl nesting areas in the prairie pothole farm- and rangelands of northwestern North Dakota. The owls relied heavily on wetland-...

  2. West Nile virus and hemoparasites in captive snowy owls (Bubo scandiacus) — management strategies to optimize survival

    PubMed Central

    Harasym, Carol A.

    2008-01-01

    In August 2005, 2 members of a group of 6 captive snowy owls (Bubo scandiacus) in central Saskatchewan died of West Nile virus infection. One of these owls and 3 of the remaining owls had significant numbers of circulating hemoparasites. Management strategies are suggested to reduce morbidity and mortality. PMID:19183740

  3. Avulsion of the brachial plexus in a great horned owl (Bubo virginaus)

    USGS Publications Warehouse

    Moore, M.P.; Stauber, E.; Thomas, N.J.

    1989-01-01

    Avulsion of the brachial plexus was documented in a Great Horned Owl (Bubo virginianus). A fractured scapula was also present. Cause of these injuries was not known but was thought to be due to trauma. Differentiation of musculoskeletal injury from peripheral nerve damage can be difficult in raptors. Use of electromyography and motor nerve conduction velocity was helpful in demonstrating peripheral nerve involvement. A brachial plexus avulsion was suspected on the basis of clinical signs, presence of electromyographic abnormalities in all muscles supplied by the nerves of the brachial plexus and absence of median-ulnar motor nerve conduction velocities.

  4. Penetrating keratoplasty for treatment of corneal protrusion in a great horned owl (Bubo virginianus).

    PubMed

    Andrew, Stacy E; Clippinger, Tracy L; Brooks, Dennis E; Helmick, Kelly E

    2002-09-01

    A young adult great horned owl (Bubo virginianus) was examined following presumed trauma. The owl had soft tissue injury to its left wing as well as corneal protrusion, lens subluxation, and iridodialysis of the right eye. The bird's eye was treated surgically with a large, rectangular penetrating keratoplasty. Following escape from housing, the bird was found with partial wound dehiscence and iris prolapse 12 days post operation. Surgical repair was performed and healing progressed for 14 days, at which time the transplant dehisced and the globe was exenterated. The patient rehabilitated well until escaping from its cage again 4 weeks later, at which time it sustained an open comminuted humeral fracture and was euthanized.

  5. Sarcocystis falcatula-associated encephalitis in a free-ranging great horned owl (Bubo virginianus).

    PubMed

    Wünschmann, Arno; Rejmanek, Daniel; Cruz-Martinez, Luis; Barr, Bradd C

    2009-03-01

    A great horned owl (Bubo virginianus) was admitted to a rehabilitation clinic with severe neurologic signs that were unresponsive to supportive care. The animal was euthanatized because of a poor prognosis. Marked granulomatous encephalitis with focal brainstem malacia was detected microscopically. The brainstem was the most severely affected brain location and the only place in which schizonts and merozoites, morphologically compatible with Sarcocystis spp., were detected. Immunohistochemistry with the use of polyclonal antisera indicated the presence of Sarcocystis falcatula. The species identification of the protozoa as S. falcatula was confirmed by polymerase chain reaction. To the author's knowledge, this is the first report of spontaneous S. falcatula-associated encephalitis in a great horned owl.

  6. Home range and habitat use by Great Horned Owls (Bubo virginianus) in Southern California

    USGS Publications Warehouse

    Bennett, J.R.; Bloom, P.H.

    2005-01-01

    Great Horned Owls (Bubo virginianus) are a common, widespread species that can be found in a variety of habitats across most of North America, but little is known about their space and habitat requirements. Using radiotelemetry, location data were collected on nine male and five female Great Horned Owls to determine home range and habitat use in southern California. Owls were tracked between January 1997 and September 1998 for periods ranging from 5-17 mo. Seven owls were also followed during 13 all-night observation periods. The mean 95% adaptive kernel home-range size for females was 180 ha (range = 88-282, SE = 36) and that for males was 425 ha (range = 147-1115 ha, SE = 105). Core areas estimated by the 50% adaptive kernel averaged 27 ha (range = 7-44, SE = 7) for females and 61 ha (range = 15-187, SE = 18) for males. Owls were located in areas with varying degrees of human disturbance ranging from almost entirely urban to native oak (Quercus agrifolia) woodland. Oak/sycamore (Quercus agrifolia/Platanus racemosa) woodland and ruderal grassland (Bromus spp., Avena spp., and various other non-native invasives), were used more often than expected based on availability, but we found no correlation between home-range size and any single habitat type or habitat groups. ?? 2005 The Raptor Research Foundation, Inc.

  7. Blood lead levels and δ-ALAD inhibition in nestlings of Eurasian Eagle Owl (Bubo bubo) to assess lead exposure associated to an abandoned mining area.

    PubMed

    Gómez-Ramírez, P; Martínez-López, E; María-Mojica, P; León-Ortega, M; García-Fernández, A J

    2011-01-01

    In order to biomonitor lead contamination in Southeastern Spain, 218 blood samples from 28 to 30-day old Eurasian Eagle Owl chicks (Bubo bubo) born between 2003 and 2007 were analysed. In general, mean lead levels showed that chicks were exposed to background concentrations. However, mean levels in chicks born in an ancient and abandoned mining site ("Sierra Minera Cartagena-La Union") or in their surroundings (Geometric mean (GM) = 5.83 μg/dl, range 0.49-25.61 μg/dl), an area highly polluted by lead and other metals, were significantly higher (p < 0.001) than the rest of the population (GM = 1.66 μg/dl, range = Non detected-18.37 μg/dl). Because δ-ALAD activity is considered the best biomarker for lead exposure and effect in birds, the activity of this enzyme was also evaluated and correlated with lead levels in blood. In this study, low levels of blood lead inhibited δ-ALAD, even when lead concentrations were lower than the limits described by other authors in raptors. Adverse effects caused by this inhibition may occur when blood lead levels were above 15 μg/dl, although only eight chicks presented these concentrations in their blood. Sampling site also influenced enzymatic activity, since it decreased about 60% in the polluted area in relation to the rest. For all these reasons, further research regarding risk assessment for lead exposure in Eagle Owls nesting in the polluted area is advisable. Our results suggest that the Eurasian Eagle Owl can be considered a suitable sentinel animal for monitoring lead contamination and δ-ALAD activity can be used as a sensitive biomarker for lead exposure and effect in this species.

  8. Cross-species amplification of microsatellite markers in the Great Horned Owl Bubo virginianus, Short-eared Owl Asio flammeus and Snowy Owl B. scandiacus for use in population genetics, individual identification and parentage studies

    USGS Publications Warehouse

    Dial, Cody R.; Talbot, Sandra L.; Sage, George K.; Seidensticker, M.T.; Holt, D.W.

    2012-01-01

    Using DNA from blood and feathers, we screened twenty-four microsatellite primer pairs initially developed for six strigid owls, and four primer pairs shown to be polymorphic across avian taxa, for their utility in Great Horned Owl (Bubo virginianus), Short-eared Owl (Asio flammeus), and Snowy Owl (Bubo scandiacus). Eight of these primers reliably amplified polymorphic fragments in Great Horned Owl, eleven in Short-eared owl, and ten in Snowy Owl. Analyses of results from presumably unrelated owls demonstrate the utility of these loci for individual identification, parentage assignment, and population genetics studies.

  9. The humeroscapular bone of the great horned owl (Bubo virginianus) and other raptors.

    PubMed

    Smith, B J; Smith, S A

    1992-03-01

    A small, separate, bony density dorsal to the shoulder joint is radiographically visible in several species of large hawks and owls. Gross dissection and histological examination show the bone to lie on the deep surface of the major deltoid muscle in intimate association with the dorsal coracohumeral ligament of the shoulder joint. The tendon of the supracoracoideus muscle passes immediately cranial to the humeroscapular bone. Two ligaments distinct from the shoulder joint capsule attach the humeroscapular bone to the proximal humerus: one passes to the proximal edge of the pectoral crest of the humerus, and the other passes to the ventral tubercle of the humerus. The bone was described as the humeroscapular bone in reference to a similar fibrocartilaginous structure possessed by some birds. The humeroscapular bone is present in the great horned owl (Bubo virginianus), the screech owl (Otus asio), the barred owl (Strix varia), the red-tailed hawk (Buteo jamaicencis), the Cooper's hawk (Accipiter cooperii), and the sharp-shinned hawk (Accipiter striatus). The bone is absent in the barn owl (Tyto alba), the osprey (Pandion haliaetus), the golden eagle (Aquila chysaetos), and the turkey vulture (Cathartes aura), though some of these species possessed a similar fibrocartilaginous structure. Whether the humeroscapular structure develops as bone or cartilage in a given species may be related to other morphological features of the wing, and/or to characteristics of the predatory behavior of the species. Clinicians and anatomists dealing with birds of prey must be aware of the presence of the humeroscapular bone to avoid misinterpreting it as a fracture fragment.

  10. Validation of a QuECheRS method for analysis of neonicotinoids in small volumes of blood and assessment of exposure in Eurasian eagle owl (Bubo bubo) nestlings.

    PubMed

    Taliansky-Chamudis, A; Gómez-Ramírez, P; León-Ortega, M; García-Fernández, A J

    2017-10-01

    Neonicotinoid pesticides have gained great interest in the last years both for agricultural and domestic use. Since the information on their environmental distribution or the effects derived from exposure to ecosystems and biota is scarce, new analytical techniques are being developed for monitoring studies. In this sense, two extraction techniques based on QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) methodology to detect the neonicotinoids authorised in Spain (acetamiprid, clothianidin, dinotefuran, imidacloprid, thiacloprid, nitenpyram and thiamethoxam) were adapted and compared: a) using acetate buffer (AB); and b) using citrate buffer (CB). For detection and quantification, high performance liquid chromatography coupled with time of flight mass spectrometry (HPLC/TOF-MS) was used. The CB method provided a wide range of recoveries (68-134%) and accuracy (4-9%). The AB method provided good recoveries (59-76%, 59% corresponded to clothianidin) precision (4-11%) linearity (0.987-0.998%) and limit of quantification (2-10ng/mL) for all the compounds. To test the effectiveness of the technique, we analysed 30 blood samples of free-ranging nestlings of Eurasian eagle owl (Bubo bubo). The only compound detected, in one nestling from a dry land farming area, was imidacloprid, with a concentration of 3.28ng/mL. To our knowledge, this is the first study of neonicotinoid pesticides in free-ranging birds of prey using non-destructive samples, providing the first insight for biomonitoring studies. Further studies, including toxicokinetics and toxicodynamics, are recommended to assess the risk for these species. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Proventriculitis associated with Cryptosporidium baileyi in a snowy owl (Bubo scandiacus) and its epidemiological investigation.

    PubMed

    Nakagun, Shotaro; Horiuchi, Noriyuki; Sugimoto, Miki; Tomikawa, Sohei; Watanabe, Kenichi; Kobayashi, Yoshiyasu

    2017-05-20

    We describe an unusual case of proventriculitis associated with Cryptosporidium baileyi in a 7-wk-old snowy owl (Bubo scandiacus) chick kept at a zoo. Necropsy of this animal revealed diffuse mucosal thickening of the proventriculus. Subsequent histopathological examinations of the proventriculus showed marked ductal epithelial hyperplasia with intestinal metaplasia and severe inflammatory cell infiltration in the lamina propria and submucosa. These lesions were associated with numerous periodic-acid-Schiff-positive cryptosporidia-like protozoan parasites. Moreover, oocysts found within the lamina propria had a noticeably thicker wall and were Ziehl-Neelsen-positive. PCR sequencing analyses of the 18S rDNA, actin and 70 kDa heat shock protein gene loci identified the protozoan to be C. baileyi, of which 2 novel sets of primers were designed for use with formalin-fixed paraffin-embedded tissue. An epidemiological survey was carried out at the zoo to investigate the source of infection, but all owl species surveyed proved negative of cryptosporidiosis. It is most likely that small animal vectors such as wild birds or rodents were responsible for this particular lethal case. This is the first report of C. baileyi associated with proventriculitis and also the first report of cryptosporidiosis in a raptor species in Asia.

  12. PHARMACOKINETIC PROPERTIES OF A SINGLE ADMINISTRATION OF ORAL GABAPENTIN IN THE GREAT HORNED OWL (BUBO VIRGINIANUS).

    PubMed

    Yaw, Taylor J; Zaffarano, Bianca A; Gall, Andrew; Olds, June E; Wulf, Larry; Papastavros, Efthimia; Coetzee, Johann F

    2015-09-01

    Gabapentin (1-[aminomethyl] cyclohexane acetic acid) is a γ-aminobutyric acid analogue that has been shown to be efficacious for neuropathic pain control in humans. Plasma gabapentin concentrations >2 μg/ml are considered effective in treating epilepsy in humans and are suggested to provide analgesia for neuropathic pain. This study investigated the pharmacokinetics of a single oral dose of gabapentin suspension (11 mg/kg) in great horned owls ( Bubo virginianus ). Plasma gabapentin concentrations were determined in six healthy birds for 48 hr using high-performance liquid chromatography with mass spectrometric detection. Plasma gabapentin concentrations were estimated by noncompartmental pharmacokinetic analysis. The harmonic mean (±SD) maximum concentration (Cmax), time to maximum concentration (Tmax), and elimination half-life (tv2λZ) for gabapentin (11 mg/kg) were 6.17±0.83 μg/ml, 51.43±5.66 min, and 264.60±69.35 min, respectively. In this study, plasma gabapentin concentrations were maintained above 2 μg/ml for 528 min (8.8 hr), suggesting that gabapentin administered orally every 8 hr may be appropriate in great horned owls.

  13. Fine structure of the pecten oculi in the great horned owl (Bubo virginianus).

    PubMed

    Braekevelt, C R

    1993-01-01

    The pecten oculi of the great horned owl (Bubo virginianus) has been examined by light and electron microscopy. The pecten in this species is of the pleated type and is small in comparison to the size of the eyeball. It consists of 7-8 accordion folds which are joined apically by a pigmented bridge of tissue. Within each fold are numerous capillaries, larger supply and drainage vessels and plentiful pleomorphic melanocytes. The capillaries are extremely specialized vessels, most of which display plentiful microfolds on both their luminal and abluminal surfaces although some capillaries show but a few microfolds. The endothelial cell bodies are extremely thin with most organelles located near the nucleus. All capillaries are surrounded by a thick fibrillar basal lamina which is felt to be structurally important. Pericytes are a common feature within these thickened basal laminae. The numerous melanocytes form an incomplete sheath around the capillaries and are also presumed to be fulfilling a structural role. While the morphology of the pecten in the great horned owl is certainly indicative of a heavy involvement in transport, when compared to the pecten in species that are more visually oriented it is smaller, displays fewer folds and a reduced number of microfolds within the capillaries.

  14. Fine structure of the retinal pigment epithelium of the great horned owl (Bubo virginianus).

    PubMed

    Braekevelt, C R; Thorlakson, I J

    1993-01-01

    The fine structure of the retinal epithelium (RPE), choriocapillaries and Bruch's membrane (complexus basalis) has been studied by light and electron microscopy in the great horned owl (Bubo virginianus). The RPE consists of a single layer of cuboidal cells joined laterally in the mid to basal region by a series of tight junctions forming part of the blood-ocular barrier. Basally (sclerally) the epithelial cells show numerous deep infoldings while apically (vitreally) a wealth of microvillar processes interdigitate with the photoreceptor cells. Internally the RPE cells display a large vesicular nucleus, plentiful smooth endoplasmic reticulum (SER) and polysomes with only small scattered profiles of rough endoplasmic reticulum (RER). Numerous pleomorphic mitochondria are basally located. In the light-adapted state the melanosomes are located almost exclusively within the apical processes indicating retinomotor movements. Myeloid bodies are numerous and often show ribosomes on their outer surface. Bruch's membrane is typical of avian species in that it is pentalaminate and the lamina densa is displaced towards the choriocapillaris. The choriocapillaris itself is but minimally fenestrated facing Bruch's membrane. Most fenestrations present show a single layered diaphragm while others display a double-layered diaphragm.

  15. Fine structure of the retinal photoreceptors of the great horned owl (Bubo virginianus).

    PubMed

    Braekevelt, C R

    1993-01-01

    The retinal photoreceptors of the great horned owl (Bubo virginianus) consist of rods, single cones and unequal double cones present in a ratio of about 30:1.2. In the light-adapted state the rods are stout cells which are not felt to undergo retinomotor movements. The rod outer segment consists of a stack of scalloped membranous discs enclosed by the cell membrane. The rod inner segment shows an ellipsoid of mitochondria and a wealth of rough endoplasmic reticulum (RER) and polysomes, Golgi zones and autophagic vacuoles but not hyperboloid of glycogen. Single cones show a slightly tapered outer segment, a heterogenous oil droplet and an ellipsoid of mitochondria at the apex of the inner segment. Double cones consist of a larger chief member which also displays an oil droplet and a slightly smaller accessory member which does not. Both members of the double cone as well as the single cone show a prominent ellipsoid, plentiful polysomes and RER and Golgi zones in the inner segment. Neither single nor double cones possess a condensed paraboloid of glycogen but instead show plentiful scattered glycogen particles. Along the contiguous membranes between accessory and chief cones a few presumed junctional complexes are seen near the external limiting membrane. Judging by their morphology in light-adaptation the cones of this species do not undergo photomechanical movements. Rods and cones (both types) have both invaginated (ribbon) and numerous superficial (conventional) synaptic sites. Rods are more numerous in this nocturnally active bird than is usually noted in avian species.

  16. Identification of a Novel Renal Coccidian (Apicomplexa: Eimeriidae) from the Great-Horned Owl ( Bubo virginianus ), USA.

    PubMed

    Jankovsky, Jennie M; Brand, Mabre; Gerhold, Richard W

    2017-04-01

    We diagnosed renal coccidiosis in two of five Great-horned Owls ( Bubo virginianus ) examined in eastern Tennessee, US, 2007-13. Histopathologic examination of the kidneys revealed multifocal mild-to-moderate dilation and epithelial hyperplasia of collecting ducts. Renal collecting duct epithelial cells contained intracytoplasmic microgametocytes, macrogametocytes, and sporulating and sporulated oocysts. Renal coccidiosis in affected birds did not result in significant inflammation. Sequence analysis of the amplified partial 18S short subunit ribosomal RNA coding region from examination of formalin fixed tissue by using PCR disclosed a 93% identity to Eimeria reichenowi in GenBank, suggesting a novel Eimeria sp.

  17. Pharmacokinetics of piperacillan after intramuscular injection in red-tailed hawks (Buteo jamaicensis) and great horned owls (Bubo virginianus).

    PubMed

    Robbins, P K; Tell, L A; Needham, M L; Craigmill, A L

    2000-03-01

    This study characterized and compared the pharmacokinetics of piperacillin after single 100 mg/kg i.m. injections in nine red-tailed hawks (Buteo jamaicensis) and five great horned owls (Bubo virginianus) over 48 hr by a modified agar well diffusion microbial inhibition assay. The mean maximum plasma piperacillin concentrations were 204 microg/ml and 221 microg/ml for the hawks and owls, respectively, and times of maximum concentrations were 15 min and 30 min, respectively. The calculated mean terminal elimination half-lives were 77 min in the hawks and 118 min in the owls. Area-under-the-curve values were 218 +/- 52 microg x hr/ml in the hawks and 444 +/- 104 microg x hr/ml in the owls. On the basis of the most common minimal inhibitory concentration (90%) for various bacterial isolates from clinical samples of 8 microg/ml, analysis of the data suggests that the maximum dosing interval for piperacillin at 100 mg/kg in medium sized raptors should be 4-6 hr.

  18. OPHTHALMIC REFERENCE VALUES AND LESIONS IN TWO CAPTIVE POPULATIONS OF NORTHERN OWLS: GREAT GREY OWLS (STRIX NEBULOSA) AND SNOWY OWLS (BUBO SCANDIACUS).

    PubMed

    Wills, Sarah; Pinard, Chantale; Nykamp, Stephanie; Beaufrère, Hugues

    2016-03-01

    This study established ophthalmic reference values and characterized ocular lesions in two captive populations of boreal owls, including 46 eyes of 23 great grey owls (Strix nebulosa) and 38 eyes from 19 snowy owls (Bubo scandiacus). A complete ophthalmologic exam was conducted, including neuro-ophthalmic reflexes, Schirmer tear test I (STT-I), intraocular pressure (IOP) using rebound tonometry, fluorescein staining, horizontal corneal measurements using Jameson calipers, direct and indirect ophthalmoscopy, and ocular ultrasound biometry. Eyes with an STT of <5 mm/min, outliers, and eyes with severe diseases were excluded from reference value analysis. No statistically significant differences were found between right or left eyes in either species or among individuals in different age groups and sexes. Mean intraocular pressures and Schirmer tear tests were also not statistically significantly different between great grey owls and snowy owls (IOP: 9.6 ± 2.6 mm Hg and 9.1 ± 1.9 mm Hg, respectively, and STT-I: 9.8 ± 2.8 mm/min and 9.8 ± 2.4 mm/min, respectively). However, snowy owls overall had a significantly larger eye than did great grey owls, reflected in corneal diameters (23.4 ± 1 vs. 20.0 ± 0.8 mm, respectively) and sonographic biometry. In both species, the most common ocular lesions included keratitis, cataracts, chorioretinal lesions, and abnormal pecten. Establishment of reference ocular parameters will help wildlife veterinarians and rehabilitators determine an appropriate treatment plan and will aid in correctly identifying the presence of ocular disease.

  19. Great horned owl (Bubo virginianus) dietary exposure to PCDD/DF in the Tittabawassee River floodplain in Midland, Michigan, USA.

    PubMed

    Coefield, Sarah J; Zwiernik, Matthew J; Fredricks, Timothy B; Seston, Rita M; Nadeau, Michael W; Tazelaar, Dustin L; Moore, Jeremy N; Kay, Denise P; Roark, Shaun A; Giesy, John P

    2010-10-01

    Soils and sediments in the floodplain of the Tittabawassee River downstream of Midland, Michigan, USA contain elevated concentrations of polychlorinated dibenzofurans (PCDF) and polychlorinated dibenzo-p-dioxins (PCDD). As a long-lived, resident top predator, the great horned owl (Bubo virginianus; GHO) has the potential to be exposed to bioaccumulative compounds such as PCDD/DF. Site-specific components of the GHO diet were collected along 115 km of the Tittabawassee, Pine, Chippewa, and Saginaw Rivers during 2005 and 2006. The site-specific GHO biomass-based diet was dominated by cottontail rabbits (Sylvilagus floridanus) and muskrats (Ondatra zibethicus). Incidental soil ingestion and cottontail rabbits were the primary contributors of PCDD/DF to the GHO diet. The great horned owl daily dietary exposure estimates were greater in the study area (SA) (3.3 to 5.0 ng 2,3,7,8-TCDD equivalents (TEQ(WHO-avian))/kg body wt/d) than the reference area (RA) (0.07 ng TEQ(WHO-Avian)/kg body wt/d). Hazard quotients (HQs) based on central tendency estimates of the average daily dose and no-observable-adverse effect level (NOAEL) for the screech owl and uncertainty factors were <1.0 for both the RA and the SA. Hazard quotients based on upper end estimates of the average daily dose and NOAEL were <1.0 in the RA and up to 3.4 in the SA. Environ. Toxicol. Chem. 2010;29:2350-2362. © 2010 SETAC.

  20. Rural culture and the conservation of Mackinders eagle owls (Bubo capensis mackinderi) in Kenya.

    PubMed

    Ogada, Darcy L

    2008-06-01

    The author describes her fieldwork studying a population of Mackinders eagle owls that live adjacent to small-scale farms in rural Kenya. Her study investigated the effects of farming practices on the diet and breeding ecology of the owls. She documented local people's attitudes toward owls since owls are taboo throughout Africa. She describes a typical day in the field, the community aspect of her project, her unique experiences studying owls in Kenya, and promotion of owl tourism.

  1. A new oligacanthorhynchid acanthocephalan described from the great horned owl, Bubo virginianus (Strigidae), and red-tailed hawk, Buteo jamaicensis (Accipitridae), from central Arizona, U.S.A.

    PubMed

    Bolette, David P

    2007-02-01

    Oligacanthorhynchus nickoli n. sp. (Acanthocephala: Oligacanthorhynchidae) is described from the great-horned owl, Bubo virginianus (Gmelin, 1788) (type host), and red-tailed hawk, Buteojamaicensis (Gmelin, 1788), collected in central Arizona. The new species is most similar to Oligacanthorhynchus iheringi and Oligacanthorhynchus minor, but it differs from all congeners primarily by trunk length, proboscis size and armature, egg size, geographical range, and host species. It is distinguished from the 9 Oligacanthorhynchus species occurring in avian hosts from both the Western and Eastern Hemispheres. Descriptions of juvenile forms of O. nickoli from the intestine of B. jamaicensis are provided from recently ingested cystacanths with everted proboscides.

  2. Risk assessment of great horned owls (Bubo virginianus) exposed to polychlorinated biphenyls and DDT along the Kalamazoo River, Michigan, USA.

    PubMed

    Strause, Karl D; Zwiernik, Matthew J; Im, Sook Hyeon; Bradley, Patrick W; Moseley, Pamela P; Kay, Denise P; Park, Cyrus S; Jones, Paul D; Blankenship, Alan L; Newsted, John L; Giesy, John P

    2007-07-01

    The great horned owl (GHO; Bubo virginianus) was used in a multiple lines of evidence study of polychlorinated biphenyls (PCBs) and p,p'-dichlorodiphenyltrichloroethane (DDT) exposures at the Kalamazoo River Superfund Site (KRSS), Kalamazoo, Michigan, USA. The study examined risks from total PCBs, including 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TEQWorld Health Organization [WHO]-Avian Toxicity Equivalency Factor [TEF]), and total DDTs (sum of DDT, dichlorodiphenyldichloroethylene [DDE], and dichlorodiphenyldichloroethane [DDD]; sigmaDDT) by measuring concentrations in eggs and nestling blood plasma in two regions of the KRSS (upper, lower) and an upstream reference area (RA). An ecological risk assessment compared concentrations of the contaminants of concern (COCs) in eggs or plasma to toxicity reference values. Productivity and relative abundance measures for KRSS GHOs were compared with other GHO populations. Egg shell thickness was measured to assess effects of p,p'-DDE. The concentrations of PCBs in eggs were as great as 4.7 x 10(2) and 4.0 x 10(4) ng PCB/g, wet weight at the RA and combined KRSS sites, respectively. Egg TEQ(WHO-Avian) calculated from aryl hydrocarbon receptor-active PCB congeners and WHO TEFs ranged to 8.0 and 1.9 x 10(2) pg TEQ(WHO-Avian)/g, (wet wt) at the RA and combined KRSS, respectively. Egg sigmaDDT concentrations were as great as 4.2 x 10(2) and 5.0 x 10(3) ng sigmaDDT/g (wet wt) at the RA and combined KRSS, respectively. Hazard quotients (HQs) for the upper 95% confidence interval (UCI) (geometric mean) and least observable adverse effect concentration (LOAEC) for COCs in eggs were < or = 1.0 for all sites. Hazard quotient values based on the no observable adverse effect concentration (NOAEC) 95% UCI in eggs were < or = 1.0, except at the LKRSS (PCB HQ = 3.1; TEQ(WHO-Avian) HQ = 1.3). Productivity and relative abundance measures indicated no population level effects in the UKRSS.

  3. Anticoagulant rodenticides in red-tailed hawks, Buteo jamaicensis, and great horned owls, Bubo virginianus, from New Jersey, USA, 2008-2010.

    PubMed

    Stansley, William; Cummings, Margaret; Vudathala, Daljit; Murphy, Lisa A

    2014-01-01

    Liver samples from red-tailed hawks (Buteo jamaicensis) and great horned owls (Bubo virginianus) were analyzed for anticoagulant rodenticides. Residues of one or more second generation anticoagulant rodenticides (SGARs) were detected in 81 % of red-tailed hawks and 82 % of great horned owls. The most frequently detected SGAR was brodifacoum, which was detected in 76 % of red-tailed hawks and 73 % of great horned owls. Bromadiolone was detected in 20 % of red-tailed hawks and 27 % of great horned owls. Difenacoum was detected in one great horned owl. No other ARs were detected. There were no significant differences between species in the frequency of detection or concentration of brodifacoum or bromadiolone. There was a marginally significant difference (p = 0.0497) between total SGAR residues in red-tailed hawks (0.117 mg/kg) and great horned owls (0.070 mg/kg). There were no seasonal differences in the frequency of detection or concentration of brodifacoum in red-tailed hawks. The data suggest that SGARs pose a significant risk of poisoning to predatory birds in New Jersey.

  4. Proventricular adenocarcinoma in a Humboldt penguin (Spheniscus humboldti) and a great horned owl (Bubo virginianus); identification of origin by mucin histochemistry.

    PubMed

    Yonemaru, Kayoko; Sakai, Hiroki; Asaoka, Yoshiji; Yanai, Tokuma; Fukushi, Hideto; Watanabe, Ken; Hirai, Katsuya; Masegi, Toshiaki

    2004-02-01

    Cases of proventricular neoplasm in a Humboldt penguin (Spheniscus humboldti) and a great horned owl (Bubo virginianus) were observed. Microscopically, the neoplastic cells formed branching tubules or acini in both cases. Galactose oxidase-Schiff (GOS) staining revealed that the cytoplasm of the normal surface epithelium and surface mucosubstances of the proventriculus adjacent to the neoplasm were positive in both cases. The neoplastic cells in both cases were also classified as GOS-positive. Therefore, the two proventricular neoplasms in this report were diagnosed as proventricular adenocarcinoma that arose from the proventricular surface epithelium. This study suggests that the mucosubstances, which the neoplastic cells produced, were a useful index for identifying the origin of the neoplastic cells in the birds.

  5. Recent fragmentation of the endangered Blakiston's fish owl (Bubo blakistoni) population on Hokkaido Island, Northern Japan, Revealed by Mitochondrial DNA and Microsatellite Analyses.

    PubMed

    Omote, Keita; Nishida, Chizuko; Takenaka, Takeshi; Saito, Keisuke; Shimura, Ryohji; Fujimoto, Satoshi; Sato, Takao; Masuda, Ryuichi

    2015-01-01

    Blakiston's fish owl (Bubo blakistoni) was previously widespread on Hokkaido Island, Japan, but is now distributed only in limited forest areas. The population size on Hokkaido decreased during the 20th century due to reduction and fragmentation of the owl's habitat. To elucidate temporal and spatial changes in population structure and genetic diversity, we analyzed 439 individuals collected over the last 100 years. We detected a population bottleneck and fragmentation event indicated by mitochondrial DNA (mtDNA) haplotype and microsatellite analyses. The lowest value for effective population size, which was estimated by moment and temporal methods from microsatellite data, occurred in the 1980s. Five haplotypes were found in the mtDNA control region; most haplotypes were previously widespread across Hokkaido, but have become fixed in separate areas after the bottleneck period. Genetic differentiation among local populations, as indicated by both mtDNA and microsatellite data, likely arose through population fragmentation. The owl population may have been divided into limited areas due to loss of habitats via human activities, and have lost genetic variability within the local populations through inbreeding. Our mtDNA and microsatellite data show that genetic diversity decreased in local populations, indicating the importance of individuals moving between areas for conservation of this species on Hokkaido.

  6. Pharmacokinetics of a single dose of intravenous and oral meloxicam in red-tailed hawks (Buteo jamaicensis) and great horned owls (Bubo virginianus).

    PubMed

    Lacasse, Claude; Gamble, Kathryn C; Boothe, Dawn M

    2013-09-01

    Pharmacokinetic data were determined after a single dose of meloxicam in red-tailed hawks (RTH; Buteo jamaicensis) and great horned owls (GHO; Bubo virginianus). In a nonrandomized crossover design, individual birds of each species received 1 dose of intravenous meloxicam (0.5 mg/kg i.v.; n = 7 for each species) followed by a 2-week washout period, and then each received 1 dose of oral meloxicam (0.5 mg/kg PO; n = 5 for each species). Blood samples were collected intermittently after administration, and meloxicam was detected in plasma by high-performance liquid chromatography. Time versus plasma concentration data were subjected to noncompartmental analysis. Red-tailed hawks were determined to have the shortest elimination half-life for meloxicam (0.49 +/- 0.5 hours) of any species documented. Great horned owls also eliminated meloxicam very rapidly (0.78 +/- 0.52 hours). Great horned owls achieved higher plasma concentrations (368 +/- 87 ng/mL) of meloxicam than RTH (182 +/- 167 ng/mL) after oral administration, although RTH had a markedly higher volume of distribution (832 +/- 711 mL/kg) than GHO (137.6 +/- 62.7 mL/kg). The differences in meloxicam pharmacokinetics between these 2 raptor species supports the need for species-dependent studies and underlines the challenges of extrapolating drug dosages between species. Results of this study suggest that the current recommended once-daily dosing interval of oral meloxicam is unlikely to maintain plasma concentrations anticipated to be therapeutic in either RTH or GHO, and practical dosing options are questionable for this nonsteriodal anti-inflammatory drug in these raptor species.

  7. Ecological risk assessment of great horned owls (Bubo virginianus) exposed to PCDD/DF in the Tittabawassee River floodplain in Midland, Michigan, USA.

    PubMed

    Coefield, Sarah J; Fredricks, Timothy B; Seston, Rita M; Nadeau, Michael W; Tazelaar, Dustin L; Kay, Denise P; Newsted, John; Giesy, John P; Zwiernik, Matthew J

    2010-10-01

    Soils and sediments downstream of Midland, Michigan, USA have elevated polychlorinated dibenzofuran (PCDF) and polychlorinated dibenzo-p-dioxin (PCDD) concentrations. To determine if the PCDD/DF concentrations have the potential to adversely affect terrestrial avian predators, a site-specific, multiple lines of evidence risk assessment was conducted for the great horned owl (Bubo virginianus; GHO). As long-lived resident top predators, the GHO has the potential to be exposed to relatively great concentrations of bioaccumulative compounds such as PCDD/DF. From 2005 to 2008, concentrations of PCDD/DF were measured in blood plasma of adult and nestling GHOs and addled eggs. Indicators of the condition of the population, including abundance and reproductive success, were collected along 115 km of river corridor. Fifty-five active 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) equivalents (TEQ(WHO-Avian)) nests were monitored in 21 breeding territories from 2005 to 2008. The geometric mean concentration in blood plasma of GHOs was greater in the study area (SA) than in the reference area (RA) for both adults (RA: 3.1; SA: 9.4 ng TEQ(WHO-Avian)/kg) and nestlings (RA: 0.82 ng TEQ(WHO-Avian)/kg, SA: 2.1 ng TEQ(WHO-Avian)/kg) GHOs, but less than concentrations expected to cause adverse effects based on laboratory studies. Concentrations of TEQ(WHO-Avian) in addled GHO eggs were also greater in the SA than the RA (50 and 7.3 ng/kg, wet weight, respectively), but were less than concentrations expected to cause adverse effects. The GHO population condition and productivity were both greater in the study area than in the reference area and were similar to other GHO populations. This result suggests the GHO population in the Tittabawassee River floodplain is consistent with what would be expected for this area. Environ. Toxicol. Chem. 2010;29:2341-2349. © 2010 SETAC.

  8. New data on Neodiplostomum americanum Chandler and Rausch, 1947 (Digenea: Diplostomidae), in the Great Horned Owl Bubo virginianus Gmelin, 1788 and the Eastern Screech Owl Megascops asio Linnaeus, 1758 in Mississippi, USA.

    PubMed

    Woodyard, Ethan T; Rosser, Thomas G; Griffin, Matt J

    2017-08-01

    Neodiplostomum americanum Chandler and Rausch, 1947 has been reported from six species of owls in North America. At present, there are no molecular data for this species and gene sequence data from Neodiplostomum Railliet, 1919 are limited. A freshly deceased specimen of the Great Horned Owl Bubo virginianus Gmelin, 1788 and a freshly deceased specimen of the Eastern Screech Owl Megascops asio Linnaeus, 1758 were collected in Oktibbeha County, Mississippi in 2014 and 2016, respectively. Neodiplostomum americanum were recovered from both hosts. Herein, updated morphological descriptions are supplemented with gene sequence data from conserved (18S, ITS1-5.8S, ITS2, and 28S rRNA) and fast-evolving (cytochrome c oxidase subunit 1 mtDNA) regions. Preliminary phylogenetic analysis of the genus based on cytochrome c oxidase subunit 1 gene sequence data supports the placement of N. americanum within a discrete phylogroup of the family Diplostomidae. The life history of N. americanum is unknown and currently limited to the description of the adult stage in avian hosts. The molecular data generated in this study offer insight into the phylogenetic placement of N. americanum within the Diplostomatidae and will aid in identifying different life stages in putative intermediate hosts.

  9. Pathologic and immunohistochemical findings in goshawks (Accipiter gentilis) and great horned owls (Bubo virginianus) naturally infected with West Nile virus.

    PubMed

    Wünschmann, Arno; Shivers, Jan; Bender, Jeff; Carroll, Larry; Fuller, Susan; Saggese, Miguel; van Wettere, Arnaud; Redig, Pat

    2005-06-01

    The carcasses of 25 great horned owls and 12 goshawks were investigated for West Nile virus (WNV) infection by immunohistochemistry (IHC) performed on various organs, including brain, spinal cord, heart, kidney, eye, bone marrow, spleen, liver, lungs, pancreas, intestine, and proventriculus, using a WNV-antigen-specific monoclonal antibody and by WNV-specific reverse transcriptase-polymerase chain reaction (RT-PCR), performed on fresh brain tissue only. WNV infection was diagnosed by IHC in all owls and all goshawks. WNV-specific RT-PCR amplified WNV-RNA in the brain of all goshawks but only 12 owls (48%). Cachexia was a common macroscopic finding associated with WNV infection in owls (76%). Myocarditis was occasionally macroscopically evident in goshawks (33%). Microscopically, inflammatory lesions, including lymphoplasmacytic and histiocytic encephalitis, myocarditis, endophthalmitis, and pancreatitis were present in both species but were more common and more severe in goshawks than in owls. The most characteristic brain lesion in owls was the formation of glial nodules, in particular in the molecular layer of the cerebellum, while encephalitis affecting the periventricular parenchyma of the cerebral cortex was common in the goshawks. In owls, WNV-antigen-positive cells were present usually only in very small numbers per organ. Kidney (80%), heart (39%), and cerebellum (37%) were the organs that most commonly contained WNV antigen in owls. WNV antigen was frequently widely distributed in the organs of infected goshawks, with increased amounts of WNV antigen in the heart and the cerebrum. Spleen (75%), cerebellum (66%), heart (58%), cerebrum (58%), and eye (50%) were often WNV-antigen positive in goshawks. In contrast with the goshawks, WNV antigen was not present in cerebral and retinal neurons of owls. WNV infection appears to be capable of causing fatal disease in great horned owls and goshawks. However, the distribution and severity of histologic lesions, the

  10. Pharmacokinetics of butorphanol tartrate in red-tailed hawks (Buteo jamaicensis) and great horned owls (Bubo virginianus).

    PubMed

    Riggs, Shannon M; Hawkins, Michelle G; Craigmill, Arthur L; Kass, Philip H; Stanley, Scott D; Taylor, Ian T

    2008-05-01

    To determine the pharmacokinetics of butorphanol tartrate after IV and IM single-dose administration in red-tailed hawks (RTHs) and great horned owls (GHOs). 6 adult RTHs and 6 adult GHOs. Each bird received an injection of butorphanol (0.5 mg/kg) into either the right jugular vein (IVj) or the pectoral muscles in a crossover study (1-week interval between treatments). The GHOs also later received butorphanol (0.5 mg/kg) via injection into a medial metatarsal vein (IVm). During each 24-hour postinjection period, blood samples were collected from each bird; plasma butorphanol concentrations were determined via liquid chromatography-mass spectrometry. 2- and 1-compartment models best fit the IV and IM pharmacokinetic data, respectively, in both species. Terminal half-lives of butorphanol were 0.94 +/- 0.30 hours (IVj) and 0.94 +/- 0.26 hours (IM) for RTHs and 1.79 +/- 1.36 hours (IVj), 1.84 +/- 1.56 hours (IM), and 1.19 +/- 0.34 hours (IVm) for GHOs. In GHOs, area under the curve (0 to infinity) for butorphanol after IVj or IM administration exceeded values in RTHs; GHO values after IM and IVm administration were less than those after IVj administration. Plasma butorphanol clearance was significantly more rapid in the RTHs. Bioavailability of butorphanol administered IM was 97.6 +/- 33.2% (RTHs) and 88.8 +/- 4.8% (GHOs). In RTHs and GHOs, butorphanol was rapidly absorbed and distributed via all routes of administration; the drug's rapid terminal half-life indicated that published dosing intervals for birds may be inadequate in RTHs and GHOs.

  11. Pharmacokinetics and anesthetic and cardiopulmonary effects of propofol in red-tailed hawks (Buteo jamaicensis) and great horned owls (Bubo virginianus).

    PubMed

    Hawkins, Michelle G; Wright, Bonnie D; Pascoe, Peter J; Kass, Philip H; Maxwell, Lara K; Tell, Lisa A

    2003-06-01

    To determine induction doses, anesthetic constant rate infusions (CRI), and cardiopulmonary effects of propofol in red-tailed hawks and great horned owls and propofol pharmacokinetics in the owls during CRI. 6 red-tailed hawks and 6 great horned owls. The CRI dose necessary for a loss of withdrawal reflex was determined via specific stimuli. Anesthesia was induced by IV administration of propofol (1 mg/kg/min) and maintained by CRI at the predetermined dose for 30 minutes. Heart and respiratory rates, arterial blood pressures, and blood gas tensions were obtained in awake birds and at various times after induction. End-tidal CO2 (ETCO2) concentration and esophageal temperature were obtained after induction. Propofol plasma concentrations were obtained after induction and after completion of the CRI in the owls. Recovery times were recorded. Mean +/- SD doses for induction and CRI were 4.48 +/- 1.09 mg/kg and 0.48 +/- 0.06 mg/kg/min, respectively, for hawks and 3.36 +/- 0.71 mg/kg and 0.56 +/- 0.15 mg/kg/min, respectively, for owls. Significant increases in PaCO2, HCO3, and ETCO2 in hawks and owls and significant decreases in arterial pH in hawks were detected. A 2-compartment model best described the owl pharmacodynamic data. Recovery times after infusion were prolonged and varied widely. Central nervous system excitatory signs were observed during recovery. Effects on blood pressure were minimal, but effective ventilation was reduced, suggesting the need for careful monitoring during anesthesia. Prolonged recovery periods with moderate-to-severe excitatory CNS signs may occur in these species at these doses.

  12. A cephalic influence on gastric motility upon seeing food in domestic turkeys (Melagris gallopavo), great-horned owls (Bubo virginianus) and red-tailed hawks (Buteo jamaicensis).

    PubMed

    Duke, G E; Evanson, O A; Redig, P T

    1976-11-01

    Strain gage transducers were permanently implanted on the muscular stomachs of 13 turkeys, 3 great-horned owls and 2 red-tailed hawks to monitor gastric motility before, during and after eating. Following fasting, the sight of food resulted in significant increases in gastric contractile activity in all three species. Gastric motility further increased when the birds were allowed to eat. In raptors, however, a brief interruption in gastric motility occurred immediately after eating. This is apparently analogous to receptive relaxation which occurs in the stomach of mammals.

  13. You are what you eat: stable isotope ecology of owl diets in Alberta, Canada

    Treesearch

    James M. Duxbury; Geoffery L. Holroyd

    1997-01-01

    Stable isotope ratio analysis (SIRA) was used to analyze the trophic level of the diets of three owl species: Barred Owl (Strix varia), Northern Hawk Owl (Surnia ulula) and Great Horned Owl (Bubo virginianus). Barred Owl and Northern Hawk Owl had diets from a similar trophic level. Both the Barred Owl and...

  14. Horner's syndrome in an African spotted eagle owl (Bubo africanus).

    PubMed

    Williams, D L; Cooper, J E

    1994-01-15

    An unilateral ptosis in an African spotted eagle own was ameliorated by topical treatment with phenylephrine, strongly suggesting a diagnosis of Horner's syndrome, the first recorded case of this syndrome in a bird.

  15. Metabolic rate and evaporative water loss of Mexican Spotted and Great Horned Owls

    Treesearch

    Joseph L. Ganey; Russell P. Balda; Rudy M. King

    1993-01-01

    We measured rates of oxygen consumption and evaporative water loss (EWL) of Mexican Spotted (Strix occidentalis lucida) and Great Horned (Bubo virginianus) owls in Arizona. Basal metabolic rate averaged 0.84 ccO2. g-1. h-1...

  16. Mutual mortality of great horned owl and southern black racer: a potential risk of raptors preying on snakes

    Treesearch

    Roger W. Perry; Raymond E. Brown; D. Craig Rudolph

    2001-01-01

    We encountered a dead southern black racer snake (Coluber constrictor priapus) coiled around a dead Great Horned Owl (Bubo virginianus). We suggest the owl was strangled by the snake before the snake did of wounds inflicted by the owl. There are previous reports of intense physical struggle between Great Horned Owls (and...

  17. S1P-Dependent Trafficking of Intracellular Yersinia pestis through Lymph Nodes Establishes Buboes and Systemic Infection

    PubMed Central

    St. John, Ashley L.; Ang, W.X. Gladys; Huang, Min-Nung; Kunder, Christian A.; Chan, Elizabeth W.; Gunn, Michael D.; Abraham, Soman N.

    2015-01-01

    SUMMARY Pathologically swollen lymph nodes (LNs), or buboes, characterize Yersinia pestis infection, yet how they form and function is unknown. We report that colonization of the draining LN (dLN) occurred due to trafficking of infected dendritic cells and monocytes in temporally distinct waves in response to redundant chemotactic signals, including through CCR7, CCR2, and sphingosine-1-phospate (S1P) receptors. Retention of multiple subsets of phagocytes within peripheral LNs using the S1P receptor agonist FTY720 or S1P1-specific agonist SEW2871 increased survival, reduced colonization of downstream LNs, and limited progression to transmission-associated septicemic or pneumonic disease states. Conditional deletion of S1P1 in mononuclear phagocytes abolished node-to-node trafficking of infected cells. Thus, Y. pestis-orchestrated LN remodeling promoted its dissemination via host cells through the lymphatic system but can be blocked by prevention of leukocyte egress from DLNs. These findings define a novel trafficking route of mononuclear phagocytes and identify S1P as a therapeutic target during infection. PMID:25238098

  18. Banding of Asio Owls in south-central Saskatchewan

    Treesearch

    C. Stuart Houston

    1997-01-01

    During a long-term Great Horned Owl (Bubo virginianus) banding program, 1946-1996, there were opportunities to band 507 Long-eared Owls (Asio otus) and 246 Short-eared Owls (Asio flammeus). No less than 35.1 percent of the Long-eared Owls and 63.5 percent of the Short-eared Owls were banded in two unusual years,...

  19. Herpersvirus strigis: host spectrum and distribution in infected owls.

    PubMed

    Burtscher, H; Sibalin, M

    1975-04-01

    Herpesvirus strigis, a new species of the genus Herpesvirus, is a pathogen for several species of owls in the order Srigiformes. Natural infection has been observed in the Eagle Owl (Bubo bubo L.), Long-eared Owl (Asio otus L.) and Snowy Owl (nyctea scandiaca L.) In addition the Little Owl (Athene noctua Scopolic) and Tengmalms Owl (Aegolius funereus L.) was experimentally infected. On the other hand the Tawny Owl (Strix aluco L.) and Barn Owl (Tyto albo Scopoli) proved resistant to a massive experimental infection. Of representatives from nine other orders of birds and mammals, only the Old World Kestrel (Falco tinnunculus L.) was found susceptible to this virus. Distribution of viral antigen in various organs of infected owls, as determined by immunofluorescence and by quantitative virus assay, was in accordance with the occurrence of macroscopic and microscopic lesions.

  20. Heavy-metal concentrations in three owl species from Korea.

    PubMed

    Kim, Jungsoo; Lee, Hang; Koo, Tae-Hoe

    2008-01-01

    This study presents concentrations of heavy metals (iron, zinc, manganese, copper, lead, and cadmium) in livers of three owl species from Korea. Essential trace elements (iron, zinc, manganese, and copper) did not differ among the owl species. We suggest that the essential elements are within the normal range and are maintained by normal homeostatic mechanisms. Lead and cadmium concentrations in Eurasian Eagle Owls (Bubo bubo) were significantly lower than in Brown Hawk Owls (Nixos scutulata) and Collared Scops Owls (Otus lempiji). Lead and cadmium concentrations in Korean owl species were at background levels; lead concentrations in two Collared Scops Owls were above background concentrations. Lead and cadmium concentrations were similar to concentrations previously reported in owls from other parts of the world. We suggest that lead and cadmium concentrations in Korean owls are below toxic concentrations.

  1. An indirect dispersal pathway for spotted knapweed seeds via deer mice and great-horned owls

    Treesearch

    Dean E. Pearson; Yvette K. Ortega

    2001-01-01

    Spotted Knapweed (Centaurea maculosa) seeds were found in the pellets of Great Horned Owls (Bubo virginianus). That apparently resulted from owls preying upon Deer Mice (Peromyscus maniculatus) which had incidentally consumed knapweed seeds while foraging for the larvae of biological control agents within...

  2. Comparative habitat use of sympatric Mexican spotted and great horned owls

    Treesearch

    Joseph L. Ganey; William M. Block; Jeffrey S. Jenness; Randolph A. Wilson

    1997-01-01

    To provide information on comparative habitat use, we studied radiotagged Mexican spotted owls (Strix occidentalis lucida: n = 13) and great horned owls (Bubo virginianus: n = 4) in northern Arizona. Home-range size (95% adaptive kernel estimate) did not differ significantly between species during either the breeding or nonbreeding...

  3. Dietary overlap between sympatric Mexican spotted and great horned owls in Arizona

    Treesearch

    Joseph L. Ganey; William M Block

    2005-01-01

    We estimated diet composition of sympatric Mexican spotted (Strix occidentalis lucida, n = 7 pairs of owls) and great horned owls (Bubo virginianus, n = 4 pairs) in ponderosa pine (Pinus ponderosa) - Gambel oak (Quercus gambelii) forest, northern Arizona. Both species preyed on mammals...

  4. [Parasite fauna of Austrian owls (Strigiformes)].

    PubMed

    Kutzer, E; Frey, H; Nöbauer, H

    1982-11-01

    During the examination of 182 owls--Asio otus (51), Strix aluco (44), Bubo bubo (34), Nyctea scandiaca (15), Athene noctua (14), Otus scops (9), Tyto alba (4), Aegolius funereus (3), Glaucidium passerinum (2), Asio flammeus (2), indigenous "owls" (4)--5 protozoan species, 3 trematode species, 1 cestode species, 6 nematode species, 3 acanthocephalan species, 2 acaride species and 7 insect species could be discovered. Dermanyssus hirundinis was proved on the Long-eared Owl and Carnus hemapterus on the Barn Owl for the first time. The infestation frequency of endo- and ectoparasites was from medium to intense on an average, whereas the infestation intensity was from small to medium. The highest rates of infestation were found at nematodes. A case of "pseudoparasitism" was detected and the significance of the analyses of stomach-contents as a guarantee of diagnosis was pointed out.

  5. Black-flies and Leucocytozoon spp. as causes of mortality in juvenile Great Horned Owls in the Yukon, Canada

    Treesearch

    D. Bruce Hunter; Christoph Rohner; Doug C. Currie

    1997-01-01

    Black fly feeding and infection with the blood parasite Leucocytozoon spp. caused mortality in juvenile Great Horned Owls (Bubo virginianus) in the Yukon, Canada during 1989-1990. The mortality occurred during a year of food shortage corresponding with the crash in snowshoe hare (Lepus americanus) populations. We...

  6. Inclusion body disease in a great horned owl.

    PubMed

    Sileo, L; Carlson, H C; Crumley, S C

    1975-01-01

    The carcass of a great horned owl (Bubo virginianus), which had been found moribund in southern Ontario, was presented for necropsy. Throughout the liver and spleen were numerous white foci 1-2 mm in diameter; also noted were white plaques in the mucosae of the pharyngeal papillae and intestine. Results of light and electron microscopic studies and experimental transmission to two captive great horned owls suggested that this was a herpvirus disease similar and possibly indentical to the owl disease reported by other workers in Wiconsin and Australia.

  7. Experimental rabies in a great horned owl.

    PubMed

    Jorgenson, R D; Gough, P M; Graham, D L

    1976-07-01

    A great horned owl (Bubo virginianus) was fed the carcass of an experimentally infected rabid skunk. The bird developed antibody titer to rabies, detected by passive haemagglutination, 27 days after oral inoculation by ingestion. The owl suppressed the infection until corticosteroid administration, after which a maximum antibody titer was attained. Evidence of active rabies viral infection was seen by fluorescent antibody staining of oral swabs, corneal impression smears and histologic tissue smears, by suckling mouse inoculation of oral swab washings, and by transmission electron microcopy. No clinical signs of rabies virus infection were observed.

  8. Biological monitoring of heavy metal contaminations using owls.

    PubMed

    Kim, Jungsoo; Oh, Jong-Min

    2012-03-01

    Iron, manganese, copper, lead and cadmium were measured in the livers, muscles, kidneys and bones of Eurasian Eagle Owls (Bubo bubo), Brown Hawk Owls (Nixos scutulata) and Collared Scops Owls (Otus lempiji) from Korea. Iron concentrations by tissue within species did not differ, but there were significant differences among tissues across all species. Manganese and copper concentrations in muscles, kidneys and bones, but not livers, differed among species and also differed among tissues in the three owl species. We suggest that manganese and copper concentrations from this study were far below the level associated with their toxicity. Lead concentrations significantly differed among all species for livers and bones, and among tissues for each species. Cadmium concentrations were significantly different among species for all tissues and among tissues in Eurasian Eagle Owls and Collared Scops Owls. For most samples, lead concentrations in livers and bones, and cadmium in livers and kidneys, were within the background levels for wild birds. For some Eurasian Eagle Owls and Collared Scops Owls, lead concentrations were at an acute exposure level, whilst lead concentrations were at a chronic exposure level in Brown Hawk Owls. Cadmium concentrations were at a chronic exposure level in all three owl species. Acute and chronic poisoning was significantly correlated between indicator tissues. We suggest that lead and cadmium contamination in Eurasian Eagle Owls may reflect a Korean source, Brown Hawk Owls may reflect Korean and wintering sites, and Collared Scops Owls may reflect breeding and/or wintering sites. This journal is © The Royal Society of Chemistry 2012

  9. Superpredation increases mercury levels in a generalist top predator, the eagle owl.

    PubMed

    Lourenço, Rui; Tavares, Paula C; del Mar Delgado, Maria; Rabaça, João E; Penteriani, Vincenzo

    2011-06-01

    Superpredation can increase the length of the food chain and potentially lead to mercury (Hg) bioaccumulation in top predators. We analysed the relationship of Hg concentrations in eagle owls Bubo bubo to diet composition and the percentage of mesopredators in the diet. Hg levels were measured in the adult feathers of eagle owls from 33 owl territories in the south-western Iberian Peninsula, and in three trophic levels of their prey: primary consumers, secondary consumers and mesopredators. In addition, we studied 6,181 prey in the eagle owl diet. Hg concentrations increased along the food chain, but the concentrations in eagle owls showed considerable variation. The Hg concentration in eagle owls increased when the percentage of mesopredators in the diet increased and the percentage of primary consumers decreased. Superpredation is often related to food stress, and the associated increase in accumulation of Hg may cause additional negative effects on vertebrate top predators. Hg levels in these eagle owl populations are relatively low, but future monitoring is recommended.

  10. Sexing young snowy owls

    USGS Publications Warehouse

    Seidensticker, M.T.; Holt, D.W.; Detienne, J.; Talbot, S.; Gray, K.

    2011-01-01

    We predicted sex of 140 Snowy Owl (Bubo scandiacus) nestlings out of 34 nests at our Barrow, Alaska, study area to develop a technique for sexing these owls in the field. We primarily sexed young, flightless owls (3844 d old) by quantifying plumage markings on the remiges and tail, predicting sex, and collecting blood samples to test our field predictions using molecular sexing techniques. We categorized and quantified three different plumage markings: two types of bars (defined as markings that touch the rachis) and spots (defined as markings that do not touch the rachis). We predicted sex in the field assuming that males had more spots than bars and females more bars than spots on the remiges and rectrices. Molecular data indicated that we correctly sexed 100% of the nestlings. We modeled the data using random forests and classification trees. Both models indicated that the number and type of markings on the secondary feathers were the most important in classifying nestling sex. The statistical models verified our initial qualitative prediction that males have more spots than bars and females more bars than spots on flight feathers P6P10 for both wings and tail feathers T1 and T2. This study provides researchers with an easily replicable and highly accurate method for sexing young Snowy Owls in the field, which should aid further studies of sex-ratios and sex-related variation in behavior and growth of this circumpolar owl species. ?? 2011 The Raptor Research Foundation, Inc.

  11. Owls as biomonitors of environmental contamination

    SciTech Connect

    Sheffield, S.R.

    1995-12-31

    Exposure and effects of environmental contaminants on owls has been largely understudied. Research primarily has focused on two species, the eastern screech owl (Otus asio) and barn owl (Tyto alba). Most of this work has been conducted with captive populations at the Patuxent Wildlife Research Center in Laurel, MD. In the wild, work has been, or is currently being, conducted with great-horned owls (Bubo virginianus) at a Superfund site in Colorado and in agricultural croplands in Iowa, and barn owls at a Superfund site in Texas and in metal-contaminated regions of the Netherlands. As higher order consumers, owls bioconcentrate many different environmental contaminants through their prey. Owls have proven to be sensitive to a wide variety of toxic compounds, including PCB`s, metals, and fluoride. Endpoints examined include reproductive effects, eggshell thickness, residue analyses, cholinesterase inhibition, and induction of liver MFO`s. Much more work remains to be done using owls as biomonitors of environmental contamination, particularly with captive populations, salvaged individuals, raptor rehabilitation center birds, and with wild populations in areas around hazardous waste sites, smelters, landfills, agricultural croplands, and other major sources of environmental contamination.

  12. Owls May Use Faeces and Prey Feathers to Signal Current Reproduction

    PubMed Central

    Penteriani, Vincenzo; del Mar Delgado, Maria

    2008-01-01

    Background Many animals communicate by marking focal elements of their home range with different kinds of materials. Visual signaling has been demonstrated to play a previously unrecognized role in the intraspecific communication of eagle owls (Bubo bubo), in both territorial and parent-offspring contexts. Visual signals may play a role in a variety of circumstances in this crepuscular and nocturnal species. Methodology/Principal Findings Here, we report that a large amount of extremely visible white faeces and prey feathers appear during the breeding season on posts and plucking sites in proximity to the nest, potentially representing a way for eagle owls to mark their territory. We present descriptive and experimental evidence showing that faeces and prey remains could act as previously unrecognized visual signals in a nocturnal avian predator. This novel signaling behavior could indicate the owls' current reproductive status to potential intruders, such as other territorial owls or non-breeding floaters. Faeces and prey feather markings may also advertise an owl's reproductive status or function in mate-mate communication. Conclusions/Significance We speculate that faeces marks and plucking may represent an overlooked but widespread method for communicating current reproduction to conspecifics. Such marking behavior may be common in birds, and we may now be exploring other questions and mechanisms in territoriality. PMID:18714382

  13. Moonlight Makes Owls More Chatty

    PubMed Central

    Penteriani, Vincenzo; Delgado, María del Mar; Campioni, Letizia; Lourenço, Rui

    2010-01-01

    Background Lunar cycles seem to affect many of the rhythms, temporal patterns and behaviors of living things on Earth. Ambient light is known to affect visual communication in animals, with the conspicuousness of visual signals being largely determined by the light available for reflection by the sender. Although most previous studies in this context have focused on diurnal light, moonlight should not be neglected from the perspective of visual communication among nocturnal species. We recently discovered that eagle owls Bubo bubo communicate with conspecifics using a patch of white throat plumage that is repeatedly exposed during each call and is only visible during vocal displays. Methodology/Principal Findings Here we provide evidence that this species uses moonlight to increase the conspicuousness of this visual signal during call displays. We found that call displays are directly influenced by the amount of moonlight, with silent nights being more frequent during periods with no-moonlight than moonlight. Furthermore, high numbers of calling bouts were more frequent at moonlight. Finally, call posts were located on higher positions on moonlit nights. Conclusions/Significance Our results support the idea that moon phase affects the visual signaling behavior of this species, and provide a starting point for examination of this method of communication by nocturnal species. PMID:20098700

  14. Surveying woodland hawks with broadcasts of great horned owl vocalization

    USGS Publications Warehouse

    Mosher, James A.; Fuller, Mark R.

    1996-01-01

    Pre-recorded vocalizations of great horned owls (Bubo virginianus) broadcast into predominantly wooded habitat along roadside survey routes resulted in as many detections of resident red-shouldered hawks (Buteo lineatus) and Cooper's hawks (Accipiter cooperii) as broadcasts of each conspecific calls. Survey results for 3 species, expressed as average number of contacts/route, were directly related to the number of resident pairs located during systematic searches conducted on foot across the study area. Regression models based on road-transect counts were significant for predicting abundance of red-shouldered hawks, broad-winged hawks (Buteo platypterus), and Cooper's hawks from our study areas.

  15. Effects of pesticides on owls in North America

    USGS Publications Warehouse

    Blus, L.J.

    1996-01-01

    A literature review of the effects of pesticides on owls in North America showed that relatively few studies have been undertaken. Owls used in experiments seem as sensitive to organochlorine pesticides (OCs) as other birds of prey, but wild owls experienced few serious problems, primarily because they were exposed to lower residues in their predominately mammalian or invertebrate prey. For example, the great horned owl ( Bubo virginianus ) and the common barn-owl ( Tyto alba ) neither experienced marked changes in mortality or recruitment rates nor was there any evidence of population decreases even during the maximum period of OC pesticide use. Also, eggshell thinning was not a widespread problem. There were adverse effects on individual owls including verified records of 74 owls of six species that died from secondary or tertiary poisoning related to strychnine, organochlorines, anticholinesterases (antiChEs) and anticoagulants in 16 states within the U.S. and one province in Canada. Most of the pesticide-related deaths occurred during the 1980s, although this probably does not represent a true temporal distribution. Verified mortalities of owls probably represent a small fraction of the actual number that died from pesticides. Incidence of mortality seems biased geographically toward areas such as New York that have active ecotoxicological programs. Burrowing owl ( Speotyto cunicularia ) populations currently are decreasing throughout much of the range in the U.S. and Canada. Studies in Canada indicate that antiChE pesticides, particularly carbofuran, were responsible for the declines there.

  16. Anticoagulant rodenticides in three owl species from Western Canada, 1988-2003.

    PubMed

    Albert, Courtney A; Wilson, Laurie K; Mineau, Pierre; Trudeau, Suzanne; Elliott, John E

    2010-02-01

    Anticoagulant rodenticides are widely used to control rodent infestations. Previous studies have shown that nontarget organisms, such as birds, are at risk for both primary and secondary poisoning. This paper presents rodenticide residue information on the livers from 164 strigiformes which included barn owls (Tyto alba), barred owls (Strix varia), and great horned owls (Bubo virginianus), collected from 1988 to 2003 in the province of British Columbia and the Yukon Territory, Canada. Livers were analyzed for brodifacoum, bromadiolone, chlorophacinone, diphacinone, difethialone, and warfarin. Our results show that, of the 164 owl livers analyzed, 70% had residues of at least one rodenticide, and of these 41% had more than one rodenticide detected. Of the three species of owls examined, barred owls were most frequently exposed (92%, n = 23); brodifacoum and bromadiolone were most often detected, with liver concentrations ranging from 0.001 to 0.927 mg/kg brodifacoum, and 0.002 to 1.012 mg/kg bromadiolone. Six of the owls (three barred owls, two barn owls, and one great horned owl) were diagnosed as having died from anticoagulant poisoning; all six owls had brodifacoum residues in the liver.

  17. Owl predation on snowshoe hares: consequences of antipredator behaviour.

    PubMed

    Rohner, Christoph; Krebs, Charles J

    1996-10-01

    We show evidence of differential predation on snowshoe hares (Lepus americanus) by great horned owls (Bubo virginianus) and ask whether predation mortality is related to antipredator behaviour in prey. We predicted higher predation on (1) young and inexperienced hares, (2) hares in open habitats lacking cover to protect from owl predation, and (3) hares in above average condition assuming that rich food patches are under highest risk of predation. Information on killed hares was obtained at nest sites of owls and by monitoring hares using radio-telemetry. The availability of age classes within the hare population was established from live-trapping and field data on reproduction and survival. Great horned owls preferred juvenile over adult hares. Juveniles were more vulnerable to owl predation before rather than after dispersal, suggesting that displacement or increased mobility were not causes for this increased mortality. Owls killed ratio-collared hares more often in open than in closed forest types, and they avoided or had less hunting success in habitats with dense shrub cover. Also, owls took hares in above average condition, although it is unclear whether samples from early spring are representative for other seasons. In conclusion, these results are consistent with the hypothesis that variation in antipredator behaviours of snowshoe hares leads to differential predation by great horned owls.

  18. Gastrointestinal parasites of owls (Strigiformes) kept in captivity in the Southern region of Brazil.

    PubMed

    da Silva, Aleksandro S; Zanette, Régis A; Lara, Valéria M; Gressler, Luciane T; Carregaro, Adriano B; Santurio, Janio M; Monteiro, Silvia G

    2009-01-01

    The aim of this research was to study the gastrointestinal parasitism in 12 adult owls kept in captivity in the Southern region of Brazil. Cloacal contents of the species Rhinoptynx clamator, Tyto alba, Athene cunicularia, Megascops spp., and Bubo virginianus were evaluated. Feces and urine were collected and analyzed by the zinc sulfate centrifugal-flotation method and stained by the modified Ziehl-Neelsen technique. Eggs of Capillaria spp. and Strongylida, oocysts of Cryptosporidium spp., Eimeria spp., and Isospora spp. were observed. The birds showed no clinical signs, probably due to the mild nature of the infection.

  19. Resource partitioning among forest owls in the River of No Return Wilderness, Idaho.

    PubMed

    Hayward, G D; Garton, E O

    1988-03-01

    We studied resource partitioning among the forest owls in the River of No Return Wilderness, Idaho, during the winter and spring of 1980 and 1981. The owl assemblage consisted of five abundant species: pygmy (Glaucidium gnoma), saw-whet (Aegolius acadicus), boreal (A. funereus), western screech (Otus kennicottii), and great-horned (Bubo virginianus). Long-eared (Asio otus) and flammulated (O. flammeolus) owls were rarely observed. Information from the literature supplemented our data to describe the pattern of resource partitioning. Stepwise discriminant function analysis and multivariate analysis of variance revealed differences in macrohabitat and microhabitat. The saw-whet, boreal, western screech, and great-horned owls all preferred mammalian prey but exhibited habitat differences. They also differed in activity periods and food habits. The pygmy owl, a food and habitat generalist, foraged diurnally more than the other species and took a higher proportion of brids. The flammulated owl used areas within the territories of other owl species but specialized on forest insects. The observed pattern of resource use was interpreted to result from environmental factors, morphological limitations and interspecific competition. Differences in food and activity time, we suggest, result from environmental factors and differences in owl morphology, while present-day interspecific competition may be important in shaping habitat use. Experiments will be necessary to determine the causal factors responsible for segregation among the forest owls.

  20. Owls

    USGS Publications Warehouse

    Smith, D.G.; Ellis, D.H.; Millsap, B.A.; Pendleton, Beth Giron

    1990-01-01

    Eight species of owls regularly occur and may breed in one or more of the southeastern states. Several additional northern or western species appear irregularly as accidentals or during years of southward incursions. In the Southeast, the most common and wide- spread owls are the common barn-owl, eastern screech-owl, great horned owl and barred owl; the most restricted is the burrowing owl. The long-eared, short-eared, and northern saw-whet owls are primarily winter visitors in this region, although small and very localized nesting populations of short-eared owls may occur in Virginia. Long-eared owls and northern saw-whet owls may occur in West Virginia and northern saw-whet owls may occur in the highlands of Tennessee and North Carolina. Several owls of the Southeast are Blue-listed as threatened, endangered, or of local concern, including the common barn-owl, eastern screech-owl, burrow'ing owl and short-eared owl. The nesting status of the long-eared owl and northern saw-whet owl are still poorly known. These two owls should be included on stat and regional lists of species of special concern. Important limiting factors for all owls of the Southeast include habitat loss and human related mortality. Management issues center on obtaining a data base useful in predicting the effects of current forest management practices on owl populations and encouraging use of forestry techniques that least impact owls. Research needs include initiating studies of all aspects of the life history and habitat relationships of each owl species.

  1. Clinical and pathologic features of West Nile virus infection in native North American owls (Family strigidae).

    PubMed

    Fitzgerald, S D; Patterson, J S; Kiupel, M; Simmons, H A; Grimes, S D; Sarver, C F; Fulton, R M; Steficek, B A; Cooley, T M; Massey, J P; Sikarskie, J G

    2003-01-01

    Since the initial report of West Nile virus in the northeastern United States in 1999, the virus has spread rapidly westward and southward across the country. In the summer of 2002, several midwestern states reported increased cases of neurologic disease and mortality associated with West Nile virus infection in various native North American owl species. This report summarizes the clinical and pathologic findings for 13 captive and free-ranging owls. Affected species were all in the family Strigidae and included seven snowy owls (Nyctea scandiaca), four great-horned owls (Bubo virginianus), a barred owl (Strix varia), and a short-eared owl (Asio flammeus). Neurologic signs identified included head tilt, uncoordinated flight, paralysis, tremors, and seizures. Owls that died were screened for flaviviral proteins by immunohistochemical staining of formalin-fixed tissues, followed by specific polymerase chain reaction assay to confirm West Nile virus with fresh tissues when available. Microscopic lesions were widespread, involving brain, heart, liver, kidney, and spleen, and were typically nonsuppurative with infiltration by predominantly lymphocytes and plasma cells. Lesions in owls were much more severe than those previously reported in corvids such as crows, which are considered highly susceptible to infection and are routinely used as sentinel species for monitoring for the presence and spread of West Nile virus. This report is the first detailed description of the pathology of West Nile virus infection in Strigiformes and indicates that this bird family is susceptible to natural infection with West Nile virus.

  2. Diagnostic findings in 132 great horned owls

    USGS Publications Warehouse

    Franson, J.C.; Little, S.E.

    1996-01-01

    We reviewed diagnostic findings for 132 great horned owl (Bubo virginianus) carcasses that were submitted to the National Wildlife Health Center from 1975-93. The carcasses were collected in 24 states but most came from Colorado (N = 21), Missouri (N = 12), Oregon (N = 12), Wyoming (N = 11), Illinois (N = 10), and Wisconsin (N = 9). Forty-two birds were emaciated but presumptive causes of emaciation, including old injuries, chronic lesions in various organs, and exposure to dieldrin, were found in only 16. A greater proportion of juveniles (56%) than adults (29%) were emaciated. Twelve owls were shot and 35 died from other traumatic injuries. Poisonings were diagnosed in 11 birds, including five associated with hydrogen sulfide exposure in oil fields and six cases of agricultural pesticide poisonings. Electrocution killed nine birds and infectious diseases were found in six. Miscellaneous conditions, including egg impaction, drowning, and visceral gout were diagnosed in three of the birds and the cause of death was undetermined in 14 owls. While this review identifies major diagnostic findings in great horned owls, sample bias prevents definitive conclusions regarding actual proportional causes of mortality.

  3. 77 FR 25192 - Wild Bird Conservation Act; Receipt of Application for Approval of a Cooperative Breeding Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-27

    ... Eagle (Aquila nipalensis), Eurasian Eagle Owl (Bubo bubo), Saker Falcon (Falco cherrug), African Fish-eagle (Haliaeetus vocifer), and Southern White- faced Owl (Ptilopsis granti). The applicant wishes to be...

  4. Diversity of Quill Mites of the Family Syringophilidae (Acari: Prostigmata) Parasitizing Owls (Aves: Strigiformes) With Remarks on the Host-Parasite Relationships.

    PubMed

    Skoracki, Maciej; Unsoeld, Markus; Marciniak, Natalia; Sikora, Bozena

    2016-07-01

    The quill mite fauna of the family Syringophilidae (Acari: Prostigmata: Cheyletoidea) associated with owls (Aves: Strigiformes) is reviewed. A new genus is proposed, Neobubophilus Skoracki & Unsoeld gen. nov. It differs from closely related Bubophilus (Bubophilus Philips and Norton, 1978) by the absence of leg setae vsII in the both sexes. In addition, four new species are described: (1) Neobubophilus cunicularius Skoracki & Unsoeld sp. nov. from Athene cunicularia (Molina, 1782) (Strigidae) from Paraguay; (2) Neobubophilus atheneus Skoracki & Unsoeld sp. nov. from Athene noctua (Scopoli, 1769) and Athene brama (Temminck, 1821) (Strigidae), both from India; (3) Bubophilus tytonus Skoracki & Unsoeld sp. nov. from Tyto alba affinis (Blyth, 1862) (Tytonidae) from Cameroon, and (4) Megasyringophilus dalmas Skoracki & Unsoeld sp. nov. from Megascops choliba (Vieillot, 1817) (Strigidae) from Venezuela. The following new host species are given: Bubo bubo (Linnaeus, 1758) (Strigidae) from Nepal for Bubophilus ascalaphus (Philips and Norton 1978) and Strix woodfordii (Smith, 1834) (Strigidae) from Tanzania for Bubophilus aluconis (aluconis Nattress and Skoracki 2009). A key for syringophilid genera and species associated with owls is constructed. The host-parasite relationships of syringophilid mites and owls are discussed. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com Version of Record, first published online May 24, 2016 with fixed content and layout in compliance with Art. 8.1.3.2 ICZN.

  5. Crystalline pteridines in the stromal pigment cells of the iris of the great horned owl.

    PubMed

    Oliphant, L W

    1981-01-01

    The bright yellow color of the iris of the Great Horned Owl (Bubo virginianus) is due to unusual pigment cells in the iris stroma. These cells are spherical and contain numerous clear lipid droplets. Around the periphery of these cells are ovoid crystalline granules that are highly birefringent and vary in color from yellow to clear gray. Differential extraction of the lipid droplets and peripheral granules with lipid solvents and 2% KOH confirmed the localization of the yellow pigment in these granules. The color, solubility, fluorescence, chromatographic mobility and ultraviolet absorption of the extracted pigment suggest it is primarily xanthopterin. It is proposed that the peripheral granules are crystalline pterinosomes capable of reflecting light. Most of the cells contain yellow reflecting granules and can be considered reflecting xanthophores. Cells lying deeper in the stroma have colorless reflecting granules and can be considered pteridine containing leucophores.

  6. The musculature and pupillary response of the great horned owl iris.

    PubMed

    Oliphant, L W; Johnson, M R; Murphy, C; Howland, H

    1983-12-01

    There is considerable confusion in the literature regarding the nature of the musculature of the avian iris. The most commonly held view is that both the sphincter and dilator are striated. The iris of the Great Horned Owl (Bubo virginianus) has a complex iridial musculature consisting of three circumferential components (a myoepithelium, smooth muscle and striated muscle) and two radial components (a well-developed myoepithelium and a few striated fibers). On the basis of the anatomy and relative development of these components, and a quantitative analysis of the pupillary reflex, it is proposed that the circumferential striated muscle is the primary pupillary constrictor and radial myoepithelium is the primary dilator. The annular band of smooth muscle may play an important role in maintaining pupillary size.

  7. Spatial and temporal variation at major histocompatibility complex class IIB genes in the endangered Blakiston's fish owl.

    PubMed

    Kohyama, Tetsuo I; Omote, Keita; Nishida, Chizuko; Takenaka, Takeshi; Saito, Keisuke; Fujimoto, Satoshi; Masuda, Ryuichi

    2015-01-01

    Quantifying intraspecific genetic variation in functionally important genes, such as those of the major histocompatibility complex (MHC), is important in the establishment of conservation plans for endangered species. The MHC genes play a crucial role in the vertebrate immune system and generally show high levels of diversity, which is likely due to pathogen-driven balancing selection. The endangered Blakiston's fish owl (Bubo blakistoni) has suffered marked population declines on Hokkaido Island, Japan, during the past several decades due to human-induced habitat loss and fragmentation. We investigated the spatial and temporal patterns of genetic diversity in MHC class IIβ genes in Blakiston's fish owl, using massively parallel pyrosequencing. We found that the Blakiston's fish owl genome contains at least eight MHC class IIβ loci, indicating recent gene duplications. An analysis of sequence polymorphism provided evidence that balancing selection acted in the past. The level of MHC variation, however, was low in the current fish owl populations in Hokkaido: only 19 alleles were identified from 174 individuals. We detected considerable spatial differences in MHC diversity among the geographically isolated populations. We also detected a decline of MHC diversity in some local populations during the past decades. Our study demonstrated that the current spatial patterns of MHC variation in Blakiston's fish owl populations have been shaped by loss of variation due to the decline and fragmentation of populations, and that the short-term effects of genetic drift have counteracted the long-term effects of balancing selection.

  8. Are red-tailed hawks and great horned owls diurnal-nocturnal dietary counterparts?

    USGS Publications Warehouse

    Marti, C.D.; Kochert, Michael N.

    1995-01-01

    Red-tailed Hawks (Buteo jamaicensis) and Great Homed Owls (Bubo virginianus)are common in North America where they occupy a wide range of habitats, often sympatrically. The two species are similar in size and have been portrayed as ecological counterparts, eating the same prey by day and night. We tested the trophic similarity of the two species by comparing published dietary data from across the United States. Both species ate primarily mammals and birds, and mean proportions of those two prey types did not differ significantly between diets of the two raptors. Red-tailed Hawks ate significantly more reptiles, and Great Homed Owls significantly more invertebrates. Dietary diversity was not significantly different at the level of prey taxonomic class, and diet overlap between the two species averaged 91%. At the prey species level, dietary overlap averaged only 50%, and at that level Red-tailed Hawk dietary diversity was significantly greater than that of Great Horned Owls. Mean prey mass of Red-tailed Hawks was significantly greater than that of Great Homed Owls. Populations of the two species in the western United States differed trophically more than did eastern populations. We conclude that, although the two species are generalist predators, they take largely different prey species in the same localities resulting in distinctive trophic characteristics.

  9. Fine structure of the pecten oculi of the barred owl (Strix varia).

    PubMed

    Smith, B J; Smith, S A; Braekevelt, C R

    1996-01-01

    The pecten oculi of the barred owl (Strix varia) has been examined by light and transmission electron microscopy. The pecten in this species is of the pleated type and is small in comparison to the size of the ocular globe. The pecten consists of 8-10 accordion-like folds that are linked apically by a pigmented tissue bridge. Each fold contains numerous capillaries, larger supply and drainage vessels, and abundant pleomorphic melanocytes. Most of these capillaries are extremely specialized vessels that possess plentiful microfolds on both the luminal and abluminal surfaces. Some capillaries however display only a few microfolds. The endothelial cell bodies are extremely attenuated, with most organelles located near the nucleus. All capillaries are surrounded by a very thick fibrillar basal lamina, which is thought to provide structural support to these small vessels. Pericytes are commonly found within these thickened basal laminae. Numerous melanocytes are also present, with processes that form an incomplete sheath around the capillaries. These processes are also presumed to provide structural support for the capillaries. As in other avian species, the morphology of the barred owl pecten is indicative of extensive involvement in substance transport. When compared to the pecten of more visually-oriented species, this pecten is smaller, has fewer folds, and displays a reduced number of microfolds within the capillaries. In these and other features, the barred owl pecten is similar to the pecten of the great horned owl (Bubo virginianus).

  10. Genetic Signatures of Demographic Changes in an Avian Top Predator during the Last Century: Bottlenecks and Expansions of the Eurasian Eagle Owl in the Iberian Peninsula

    PubMed Central

    Graciá, Eva; Ortego, Joaquín; Godoy, José Antonio; Pérez-García, Juan Manuel; Blanco, Guillermo; del Mar Delgado, María; Penteriani, Vincenzo; Almodóvar, Irene; Botella, Francisco; Sánchez-Zapata, José Antonio

    2015-01-01

    The study of the demographic history of species can help to understand the negative impact of recent population declines in organisms of conservation concern. Here, we use neutral molecular markers to explore the genetic consequences of the recent population decline and posterior recovery of the Eurasian eagle owl (Bubo bubo) in the Iberian Peninsula. During the last century, the species was the object of extermination programs, suffering direct persecution by hunters until the 70’s. Moreover, during the last decades the eagle owl was severely impacted by increased mortality due to electrocution and the decline of its main prey species, the European rabbit (Oryctolagus cuniculus). In recent times, the decrease of direct persecution and the implementation of some conservation schemes have allowed the species’ demographic recovery. Yet, it remains unknown to which extent the past population decline and the later expansion have influenced the current species’ pattern of genetic diversity. We used eight microsatellite markers to genotype 235 eagle owls from ten Spanish subpopulations and analyse the presence of genetic signatures attributable to the recent population fluctuations experienced by the species. We found moderate levels of differentiation among the studied subpopulations and Bayesian analyses revealed the existence of three genetic clusters that grouped subpopulations from central, south-western and south-eastern Spain. The observed genetic structure could have resulted from recent human-induced population fragmentation, a patchy distribution of prey populations and/or the philopatric behaviour and habitat selection of the species. We detected an old population bottleneck, which occurred approximately 10,000 years ago, and significant signatures of recent demographic expansions. However, we did not find genetic signatures for a recent bottleneck, which may indicate that population declines were not severe enough to leave detectable signals on the

  11. Genetic Signatures of Demographic Changes in an Avian Top Predator during the Last Century: Bottlenecks and Expansions of the Eurasian Eagle Owl in the Iberian Peninsula.

    PubMed

    Graciá, Eva; Ortego, Joaquín; Godoy, José Antonio; Pérez-García, Juan Manuel; Blanco, Guillermo; Delgado, María del Mar; Penteriani, Vincenzo; Almodóvar, Irene; Botella, Francisco; Sánchez-Zapata, José Antonio

    2015-01-01

    The study of the demographic history of species can help to understand the negative impact of recent population declines in organisms of conservation concern. Here, we use neutral molecular markers to explore the genetic consequences of the recent population decline and posterior recovery of the Eurasian eagle owl (Bubo bubo) in the Iberian Peninsula. During the last century, the species was the object of extermination programs, suffering direct persecution by hunters until the 70's. Moreover, during the last decades the eagle owl was severely impacted by increased mortality due to electrocution and the decline of its main prey species, the European rabbit (Oryctolagus cuniculus). In recent times, the decrease of direct persecution and the implementation of some conservation schemes have allowed the species' demographic recovery. Yet, it remains unknown to which extent the past population decline and the later expansion have influenced the current species' pattern of genetic diversity. We used eight microsatellite markers to genotype 235 eagle owls from ten Spanish subpopulations and analyse the presence of genetic signatures attributable to the recent population fluctuations experienced by the species. We found moderate levels of differentiation among the studied subpopulations and Bayesian analyses revealed the existence of three genetic clusters that grouped subpopulations from central, south-western and south-eastern Spain. The observed genetic structure could have resulted from recent human-induced population fragmentation, a patchy distribution of prey populations and/or the philopatric behaviour and habitat selection of the species. We detected an old population bottleneck, which occurred approximately 10,000 years ago, and significant signatures of recent demographic expansions. However, we did not find genetic signatures for a recent bottleneck, which may indicate that population declines were not severe enough to leave detectable signals on the species

  12. Pulsed resources at tundra breeding sites affect winter irruptions at temperate latitudes of a top predator, the snowy owl.

    PubMed

    Robillard, A; Therrien, J F; Gauthier, G; Clark, K M; Bêty, J

    2016-06-01

    Irruptive migration is mostly observed in species specialized on pulsed resources and is thought to be a response to unpredictable changes in food supply. We assessed two alternative hypotheses to explain the periodic winter irruptions of snowy owls Bubo scandiacus every 3-5 years in temperate North America: (a) the lack-of-food hypothesis, which states that a crash in small mammal abundance on the Arctic breeding grounds forces owls to move out of the tundra massively to search for food in winter; (b) the breeding-success hypothesis, which states that high abundance of tundra small mammals during the summer allows for high production of young, thus increasing the pool of migrants moving south the following winter. We modeled winter irruptions of snowy owls in relation to summer food resources and geographic location. Winter abundance of owls was obtained from citizen-based surveys from 1994 to 2011 and summer abundance of small mammals was collected in summer at two distant sites in Canada: Bylot Island, NU (eastern High Arctic) and Daring Lake, NWT (central Low Arctic). Winter owl abundance was positively related to prey abundance during the previous summer at both sites and tended to decrease from western to eastern temperate North America. Irruptive migration of snowy owls was therefore best explained by the breeding success hypothesis and was apparently caused by large-scale summer variations in food. Our results, combined with previous findings, suggest that the main determinants of irruptive migration may be species specific even in a guild of apparently similar species.

  13. Spatial selectivity and binaural responses in the inferior colliculus of the great horned owl.

    PubMed

    Volman, S F; Konishi, M

    1989-09-01

    In this study we have investigated the processing of auditory cues for sound localization in the great horned owl (Bubo virginianus). Previous studies have shown that the barn owl, whose ears are asymmetrically oriented in the vertical plane, has a 2-dimensional, topographic representation of auditory space in the external division of the inferior colliculus (ICx). As in the barn owl, the great horned owl's ICx is anatomically distinct and projects to the optic tectum. Neurons in ICx respond over only a small range of azimuths (mean = 32 degrees), and azimuth is topographically mapped. In contrast to the barn owl, the great horned owl has bilaterally symmetrical ears and its receptive fields are not restricted in elevation. The binaural cues available for sound localization were measured both with cochlear microphonic recordings and with a microphone attached to a probe tube in the auditory canal. Interaural time disparity (ITD) varied monotonically with azimuth. Interaural intensity differences (IID) also changed with azimuth, but the largest IIDs were less than 15 dB, and the variation was not monotonic. Neither ITD nor IID varied systematically with changes in the vertical position of a sound source. We used dichotic stimulation to determine the sensitivity of ICx neurons to these binaural cues. Best ITD of ICx units was topographically mapped and strongly correlated with receptive-field azimuth. The width of ITD tuning curves, measured at 50% of the maximum response, averaged 72 microseconds. All ICx neurons responded only to binaural stimulation and had nonmonotonic IID tuning curves. Best IID was weakly, but significantly, correlated with best ITD (r = 0.39, p less than 0.05). The IID tuning curves, however, were broad (mean 50% width = 24 dB), and 67% of the units had best IIDs within 5 dB of 0 dB IID. ITD tuning was sensitive to variations in IID in the direction opposite to that expected for time-intensity trading, but the magnitude of this effect was only

  14. Diet and trophic characteristics of great horned owls in southwestern Idaho

    USGS Publications Warehouse

    Marti, C.D.; Kochert, Michael N.

    1996-01-01

    We studied the diet of Great Horned Owls (Bubo virginianus) in the Snake River Birds of Prey National Conservation Area in southwestern Idaho for 14 breeding seasons. The diet included 89.2% mammals by number and 91.2% by mass. Kangaroo rats (Dipodomys spp.) were the most common prey overall, but montane voles (Microtus montanus), Peromyscus spp., Great Basin pocket mice (Perognathus parvus) and Townsend's pocket gophers (Thomomys towsendii) were most common at some collection sites. Estimated mean mass of prey was 44.5 g (range 20.5-82.6 g at individual nests), and food-niche breadth (dietary diversity estimated by $1/\\Sigma p_{{\\rm i}}{}^{2}$) was 7.32 (range 1.55-6.85 at individual nests). Lower mean overlap in diet occurred between nests in the same year than between years at the same nest. Species of prey taken were significantly correlated with the general habitat types in which the nest was located. Diets of owls in areas of intensive agriculture overlapped little (42%) with those in rangeland habitats.

  15. Use of whole blood lymphocyte stimulation test for immunocompetency studies in bald eagles, red-tailed hawks, and great horned owls.

    PubMed

    Redig, P T; Dunnette, J L; Sivanandan, V

    1984-11-01

    Mitogen-induced whole blood lymphocyte stimulation tests for immunocompetency studies in bald eagles (Haliaeetus leucocephalus), red-tailed hawks (Buteo jamaicensis), and great horned owls (Bubo virginianus) were developed. Combinations of incubation times, blood dilutions, concentrations of [3H]thymidine and [125I]2-deoxyuridine, antibiotics, phytohemagglutinin-P, and concanavalin A were tested for their effects on the stimulation index (SI). An antibiotic combination of gentamicin plus amphotericin B yielded low SI with lymphocytes from bald eagles, but not with lymphocytes from great horned owls or red-tailed hawks. Penicillin plus streptomycin caused no such depression of SI. Lymphocytes from all 3 species yielded maximum responses with a 48-hour prelabel and 12- to- 16 hour postlabel incubation period at 41 C and 1:20 blood dilution. Optimal mitogen concentrations for lymphocytes from bald eagles, red-tailed hawks, and great horned owls were 25 micrograms, 10 micrograms, and 10 micrograms of phytohemagglutinin-P/well, respectively, and 2.5 micrograms, 10 micrograms, and 10 micrograms of concanavalin A/well, respectively. Differences in SI were not seen between the 2 radioactive labels. The optimal concentration of the [3H]thymidine label ranged from 0.06 to 0.125 microCi/well.

  16. Plasma to egg conversion factor for evaluating polychlorinated biphenyl and DDT exposures in great horned owls and bald eagles.

    PubMed

    Strause, Karl D; Zwiernik, Matthew J; Im, Sook Hyeon; Newsted, John L; Kay, Denise P; Bradley, Patrick W; Blankenship, Alan L; Williams, Lisa L; Giesy, John P

    2007-07-01

    The benefits of nondestructive sampling techniques, such as plasma sampling, to directly measure contaminant exposure levels in at-risk or protected raptor populations are many. However, such assays are generally inconsistent with the most certain source of toxicity reference values, which are based on feeding studies and quantified as dietary or "in ovo" (egg-based) concentrations. An accurate conversion factor to translate nondestructive plasma-based contaminant concentrations to comparable egg-based concentrations will prove valuable to risk assessors investigating the potential effects of chemical exposures to raptors. We used databases describing the concentrations of total polychlorinated biphenyls (PCBs) in great horned owls (GHO; Bubo virginianus) and total PCBs and p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) in bald eagles (Haliaeetus leucocephalus) from the Great Lakes region (Michigan, Wisconsin, USA) to develop a relationship to predict concentrations of PCBs and DDE in eggs. To develop a robust predictive relationship, all of the source data included concentrations of both total PCBs and/or DDE for nestling blood plasma and egg samples collected from within discrete active nesting territories and, in most instances, the same nest. The key characteristics (slope and elevation) of each relationship were tested for differences related to species and geographic region. Predicted variability of relationships were examined and compared to variability associated with natural systems. The results of statistical testing indicate that applying the conversion factors between species (GHO to bald eagle) and among geographic regions yields predicted egg concentrations that are not statistically dissimilar and are within the natural variability observed for residue concentrations among eggs of raptors within species and region.

  17. Lead in hawks, falcons and owls downstream from a mining site on the Coeur D'Alene river, Idaho

    USGS Publications Warehouse

    Henny, C.J.; Blus, L.J.; Hoffman, D.J.; Grove, R.A.

    1994-01-01

    Mining and smelting at Kellogg-Smelterville, Idaho, resulted in high concentrations of lead in Coeur d'Alene (CDA) River sediments and the floodplain downstream, where American Kestrels (Falco sparverius), Northern Harriers (Circus cyaneus), Red-tailed Hawks (Buteo jamaicensis), Great Horned Owls (Bubo virginianus), and Western Screech-owls (Otus kennicotti) nested. Nestling American Kestrels contained significantly higher (P=0.0012) blood lead concentrations along the CDA River (0.24 ?g/g, wet wt) than the nearby reference area (0.087 ?g/g). A 35% inhibition of blood *-aminolevulinic acid dehydratase (ALAD) in nestling Northern Harriers (P=0.0001), 55% in nestling American Kestrels (P=0.0001) and 81% in adult American Kestrels (P=0.0004) provided additional evidence of lead exposure in the CDA River population. In nestling American Kestrels and Northern Harriers, ALAD activity was negatively correlated with lead in blood. An earlier report on Ospreys (Pandion haliaetus) showed slightly less inhibition of ALAD than in American Kestrels, but no significant reduction in hemoglobin or hematocrit and no negative influence on production rates. The adult and nestling American Kestrels along the CDA River contained about twice as much blood lead as Ospreys during the same years (adult 0.46 vs. 0.20 ?g/g, and nestling 0.24 vs. 0.09 ?g/g), but adults showed a 7.5% reduction in hemoglobin (P=0.0356) and nestlings an 8.2% reduction in hemoglobin (P=0.0353) and a 5.8% reduction in hematocrit (P=0.0482). We did not observe raptor deaths related to lead, and although the production rate for American Kestrels was slightly lower along the CDA River, we found no significant negative relation between productivity and lead. Limited data on the other raptors provide evidence of exposure to lead along the CDA River. Several traits of raptors apparently reduce their potential for accumulating critical levels of lead which is primarily stored in bones of prey species.

  18. Outrageous Owls

    ERIC Educational Resources Information Center

    Walkup, Nancy

    2007-01-01

    The author's encounter with a live owl and her purchase of a Peruvian folk art gourd inspired a new interdisciplinary experience for the author's fourth grade students. In this article, she describes how her students explored owls through clay sculpture. (Contains 2 resources and 1 online resource.)

  19. Outrageous Owls

    ERIC Educational Resources Information Center

    Walkup, Nancy

    2007-01-01

    The author's encounter with a live owl and her purchase of a Peruvian folk art gourd inspired a new interdisciplinary experience for the author's fourth grade students. In this article, she describes how her students explored owls through clay sculpture. (Contains 2 resources and 1 online resource.)

  20. Owl Pellets.

    ERIC Educational Resources Information Center

    Thompson, Craig D.

    1987-01-01

    Provides complete Project WILD lesson plans for 20-45-minute experiential science learning activity for grades 3-7 students. Describes how students construct a simple food chain through examination of owl pellets. Includes lesson objective, method, background information, materials, procedure, evaluation, and sources of owl pellets and posters.…

  1. Owl Pellets.

    ERIC Educational Resources Information Center

    Thompson, Craig D.

    1987-01-01

    Provides complete Project WILD lesson plans for 20-45-minute experiential science learning activity for grades 3-7 students. Describes how students construct a simple food chain through examination of owl pellets. Includes lesson objective, method, background information, materials, procedure, evaluation, and sources of owl pellets and posters.…

  2. Snowy owl

    USGS Publications Warehouse

    Smith, D.G.; Ellis, D.H.; Pendleton, Beth Giron; LeFranc, Maurice N.=; Moss, Mary Beth

    1989-01-01

    The snowy owl is a rare to uncommon, irregular winter visitor in the northeastern United States, decreasing southward in abundance except during incursion years, when it is more common and widely distributed. Although snowy owls are recorded in northern New England every winter, major incursions occur at approximately three to four year intervals. Limiting factors include food, habitat and human interference. Research is needed on the population ecology of this species and, perhaps more important, management goals must be directed towards public education emphasizing the value of snowy owls.

  3. Implementing Avian Inventory and Monitoring Efforts on Corps of Engineers Project Lands

    DTIC Science & Technology

    2007-06-01

    species (e.g., Eastern Screech Owl [Otus asio]) often respond well to calls and songs broadcast from a tape or CD player; therefore, incorporating a tape...Grasshopper Sparrow (Ammodramus savannarum), Lark Sparrow (Chondestes grammacus), and Eastern Meadowlark (Sternella magna)) (Askins 1993, Herkert 1994...species include many gull (Larus spp.) and tern (Sterna spp.) species, and many owl (e.g., Great-horned Owl [Bubo virgini- anus]) or nightjars

  4. Spotted Owl: Strix occidentalis

    Treesearch

    Joseph L. Ganey

    1997-01-01

    The scientific name, Strix occidentalis, translates as "owl of the west," an appropriate name for this inhabitant of western forests. The subspecies found in Arizona, the Mexican Spotted Owl, is S. o. lucida - "light" or "bright" owl of the west. This race is generally lighter in color than Spotted...

  5. Owls On Silent Wings. The Wonder Series.

    ERIC Educational Resources Information Center

    Cooper, Ann C.

    This curriculum guide is all about owls and provides information on the folklore related to owls, present populations, explanations of physical characteristics, exploring owl pellets, burrowing owls, snowy owls, and great horned owls. Included are eight activities using owl cards, owl pellets, puzzles, and origami. This guide aims to increase…

  6. Owls On Silent Wings. The Wonder Series.

    ERIC Educational Resources Information Center

    Cooper, Ann C.

    This curriculum guide is all about owls and provides information on the folklore related to owls, present populations, explanations of physical characteristics, exploring owl pellets, burrowing owls, snowy owls, and great horned owls. Included are eight activities using owl cards, owl pellets, puzzles, and origami. This guide aims to increase…

  7. Owl: electronic datasheet generator.

    PubMed

    Appleton, Evan; Tao, Jenhan; Wheatley, F Carter; Desai, Devina H; Lozanoski, Thomas M; Shah, Pooja D; Awtry, Jake A; Jin, Shawn S; Haddock, Traci L; Densmore, Douglas M

    2014-12-19

    Owl ( www.owlcad.org ) is a biodesign automation tool that generates electronic datasheets for synthetic biological parts using common formatting. Data can be retrieved automatically from existing repositories and modified in the Owl user interface (UI). Owl uses the data to generate an HTML page with standard typesetting that can be saved as a PDF file. Here we present the Owl software tool in its alpha version, its current UI, its description of input data for generating a datasheet, its example datasheets, and the vision of the tool's role in biodesign automation.

  8. Cryptococcus neoformans var neoformans isolated from droppings of captive birds in Nigeria.

    PubMed

    Irokanulo, E O; Makinde, A A; Akuesgi, C O; Ekwonu, M

    1997-04-01

    The yeast, Cryptococcus neoformans, was found in apparently healthy birds at the Jos Wildlife Park and Zoo in Jos, Nigeria. Cryptococcus neoformans var neoformans was isolated from feces of four captive bird species. Five isolates belonged to serotype A while two were serotype D. Serotype A of C. neoformans was isolated from a white face duck (Dendrocygna viduata), eagle owl (Bubo africanus cinerascene) and peacock (Pavo cristatus). The other two (serotype D), were isolated from a spotted eagle owl.

  9. Learning from an Owl.

    ERIC Educational Resources Information Center

    Greeves, Adrian

    1988-01-01

    Describes one creative writing teacher's use of an owl as a focal point for writing activities and how the writing activities aided the students' personal and creative development. Provides samples of student writing. (ARH)

  10. Mixed-Media Owls

    ERIC Educational Resources Information Center

    Schultz, Kathy

    2010-01-01

    The fun of creating collages is there are unlimited possibilities for the different kinds of materials one can use. In this article, the author describes how her eighth-grade students created an owl using mixed media.

  11. Mixed-Media Owls

    ERIC Educational Resources Information Center

    Schultz, Kathy

    2010-01-01

    The fun of creating collages is there are unlimited possibilities for the different kinds of materials one can use. In this article, the author describes how her eighth-grade students created an owl using mixed media.

  12. Learning from an Owl.

    ERIC Educational Resources Information Center

    Greeves, Adrian

    1988-01-01

    Describes one creative writing teacher's use of an owl as a focal point for writing activities and how the writing activities aided the students' personal and creative development. Provides samples of student writing. (ARH)

  13. Demographic response of northern spotted owls to barred owl removal

    USGS Publications Warehouse

    Diller, V. Lowell; Hamm, Keith A; Early, Desiree A; Lamphear, David W; Katie Dugger,; Yackulic, Charles B.; Schwarz, Carl J.; Carlson, Peter C.; McDonald, Trent L.

    2016-01-01

    Federally listed as threatened in 1990 primarily because of habitat loss, the northern spotted owl (Strix occidentalis caurina) has continued to decline despite conservation efforts resulting in forested habitat being reserved throughout its range. Recently, there is growing evidence the congeneric invasive barred owl (Strix varia) may be responsible for the continued decline primarily by excluding spotted owls from their preferred habitat. We used a long-term demographic study for spotted owls in coastal northern California as the basis for a pilot barred owl removal experiment. Our demography study used capture–recapture, reproductive output, and territory occupancy data collected from 1990 to 2013 to evaluate trends in vital rates and populations. We used a classic before-after-control-impact (BACI) experimental design to investigate the demographic response of northern spotted owls to the lethal removal of barred owls. According to the best 2-species dynamic occupancy model, there was no evidence of differences in barred or northern spotted owl occupancy prior to the initiation of the treatment (barred owl removal). After treatment, barred owl occupancy was lower in the treated relative to the untreated areas and spotted owl occupancy was higher relative to the untreated areas. Barred owl removal decreased spotted owl territory extinction rates but did not affect territory colonization rates. As a result, spotted owl occupancy increased in the treated area and continued to decline in the untreated areas. Prior to and after barred owl removal, there was no evidence that average fecundity differed on the 2 study areas. However, the greater number of occupied spotted owl sites on the treated areas resulted in greater productivity in the treated areas based on empirical counts of fledged young. Prior to removal, survival was declining at a rate of approximately 0.2% per year for treated and untreated areas. Following treatment, estimated survival was 0.859 for

  14. Owl Pellet Paleontology

    ERIC Educational Resources Information Center

    McAlpine, Lisa K.

    2013-01-01

    In this activity for the beginning of a high school Biology 1 evolution unit, students are challenged to reconstruct organisms found in an owl pellet as a model for fossil reconstruction. They work in groups to develop hypotheses about what animal they have found, what environment it inhabited, and what niche it filled. At the end of the activity,…

  15. Owl Pellet Paleontology

    ERIC Educational Resources Information Center

    McAlpine, Lisa K.

    2013-01-01

    In this activity for the beginning of a high school Biology 1 evolution unit, students are challenged to reconstruct organisms found in an owl pellet as a model for fossil reconstruction. They work in groups to develop hypotheses about what animal they have found, what environment it inhabited, and what niche it filled. At the end of the activity,…

  16. Owl Research that's Good for the Birds.

    ERIC Educational Resources Information Center

    Cristol, Daniel A.

    1986-01-01

    Describes and illustrates how to build nest boxes to provide city homes for screech owls to reestablish a healthy ecological balance. Outlines how to conduct a pellet analysis of an owl's diet and how to study screech owl territoriality. (NEC)

  17. Owl Research that's Good for the Birds.

    ERIC Educational Resources Information Center

    Cristol, Daniel A.

    1986-01-01

    Describes and illustrates how to build nest boxes to provide city homes for screech owls to reestablish a healthy ecological balance. Outlines how to conduct a pellet analysis of an owl's diet and how to study screech owl territoriality. (NEC)

  18. Environmental Assessment for Integrated Natural Resources Management Plan Activities at Eglin Air Force Base, Florida

    DTIC Science & Technology

    2013-01-28

    marilandica Great horned owl Bubo virginianus Bluejack oak Q. incana Gopher tortoise Gopherus polyphemus Wiregrass Aristida stricta Pocket gopher ...28 JAN 2013 2. REPORT TYPE Environmental Assessment 3. DATES COVERED 00-00-2010 to 00-00-2013 4. TITLE AND SUBTITLE Final Environmental...point sources that discharge pollutants into waters of the United States. USEPA State Wildlife Possession Permit Authorizes keeping gopher

  19. Synovial chondromatosis in raptors.

    PubMed

    Stone, E G; Walser, M M; Redig, P T; Rings, B; Howard, D J

    1999-01-01

    Fourteen raptors, consisting of 13 great horned owls (Bubo virginianus) and one red-tailed hawk (Buteo jamaicensis), from central and north central Minnesota, western Wisconsin, and eastern South Dakota (USA) were admitted to a raptor rehabilitation center between June 1992 and June 1995, with perisynovial and synovial chondromatosis affecting multiple joints. Birds were severely debilitated primarily due to loss of shoulder motion. The etiology of these lesions in raptors is unknown.

  20. Fatal pox infection in a rough-legged hawk

    USGS Publications Warehouse

    Pearson, G.L.; Pass, D.A.; Beggs, E.C.

    1975-01-01

    Natural pox infection occurred in a free-living rough-legged hawk (Buteo lagopus) in northeastern North Dakota. Gross, histological and electron microscopic findings were typical of pox infection, and characteristic lesions developed in red-tailed hawks (Buteo jamaicensis) but not in great horned owls (Bubo virginianus) following inoculation with case material. Death of the rough-legged hawk was attributed to starvation resulting from inability to capture prey and to blood loss from foot lesions.

  1. All about Owls: Studying Owls, State Birds, and Endangered Species.

    ERIC Educational Resources Information Center

    Rivard, Leonard P.

    1991-01-01

    Activities are included that acquaint students with the parts of birds and the structure of feathers; that identify the prey of owls by opening owl pellets; working with information about threatened and endangered species of birds; and follow-up activities for bird study. A list of state and provincial birds of the United States and Canada and…

  2. All about Owls: Studying Owls, State Birds, and Endangered Species.

    ERIC Educational Resources Information Center

    Rivard, Leonard P.

    1991-01-01

    Activities are included that acquaint students with the parts of birds and the structure of feathers; that identify the prey of owls by opening owl pellets; working with information about threatened and endangered species of birds; and follow-up activities for bird study. A list of state and provincial birds of the United States and Canada and…

  3. Owl Pellets and Crisis Management.

    ERIC Educational Resources Information Center

    Anderson, Tom

    2002-01-01

    Describes a press conference that was used as a "teachable moment" when owl pellets being used for instructional purposes were found to be contaminated with Salmonella. The incident highlighted the need for safe handling of owl pellets, having a crisis management plan, and the importance of conveying accurate information to concerned parents.…

  4. Owl Pellets and Crisis Management.

    ERIC Educational Resources Information Center

    Anderson, Tom

    2002-01-01

    Describes a press conference that was used as a "teachable moment" when owl pellets being used for instructional purposes were found to be contaminated with Salmonella. The incident highlighted the need for safe handling of owl pellets, having a crisis management plan, and the importance of conveying accurate information to concerned parents.…

  5. "Mission possible: owls in education"

    Treesearch

    Marcia J. Wilson

    1997-01-01

    A panel of four experts in the fields of environmental education, rehabilitation and research assembled for a 1-3/4 hour workshop chaired by a moderator. Each panelist reflected upon their experiences using live owls in their own environmental education and/or research programs. Permanently disabled or imprinted owls can live long, useful lives as ambassadors from the...

  6. Western Screech-Owl (Megascops kennicottii)

    Treesearch

    Frederick R. Gehlbach; Scott H. Stoleson

    2010-01-01

    The Western Screech-Owl (Megascops kennicottii) is a permanent resident and the largest of New Mexico's eight small owls. At an average 116 g (4.1 oz), it is 1.3 times more massive than the Whiskered Screech-Owl (M. trichopsis) but similar to the Eastern Screech-Owl (M. asio), the state's other two small owls with dark-streaked, white-flecked gray plumage...

  7. Blood parasites in owls with conservation implications for the Spotted Owl (Strix occidentalis).

    PubMed

    Ishak, Heather D; Dumbacher, John P; Anderson, Nancy L; Keane, John J; Valkiūnas, Gediminas; Haig, Susan M; Tell, Lisa A; Sehgal, Ravinder N M

    2008-05-28

    The three subspecies of Spotted Owl (Northern, Strix occidentalis caurina; California, S. o. occidentalis; and Mexican, S. o. lucida) are all threatened by habitat loss and range expansion of the Barred Owl (S. varia). An unaddressed threat is whether Barred Owls could be a source of novel strains of disease such as avian malaria (Plasmodium spp.) or other blood parasites potentially harmful for Spotted Owls. Although Barred Owls commonly harbor Plasmodium infections, these parasites have not been documented in the Spotted Owl. We screened 111 Spotted Owls, 44 Barred Owls, and 387 owls of nine other species for haemosporidian parasites (Leucocytozoon, Plasmodium, and Haemoproteus spp.). California Spotted Owls had the greatest number of simultaneous multi-species infections (44%). Additionally, sequencing results revealed that the Northern and California Spotted Owl subspecies together had the highest number of Leucocytozoon parasite lineages (n = 17) and unique lineages (n = 12). This high level of sequence diversity is significant because only one Leucocytozoon species (L. danilewskyi) has been accepted as valid among all owls, suggesting that L. danilewskyi is a cryptic species. Furthermore, a Plasmodium parasite was documented in a Northern Spotted Owl for the first time. West Coast Barred Owls had a lower prevalence of infection (15%) when compared to sympatric Spotted Owls (S. o. caurina 52%, S. o. occidentalis 79%) and Barred Owls from the historic range (61%). Consequently, Barred Owls on the West Coast may have a competitive advantage over the potentially immune compromised Spotted Owls.

  8. Blood parasites in Owls with conservation implications for the Spotted Owl (Strix occidentalis)

    USGS Publications Warehouse

    Ishak, H.D.; Dumbacher, J.P.; Anderson, N.L.; Keane, J.J.; Valkiunas, G.; Haig, S.M.; Tell, L.A.; Sehgal, R.N.M.

    2008-01-01

    The three subspecies of Spotted Owl (Northern, Strix occidentalis courina; California, S. o. occidentalis; and Mexican, S. o. lucida) are all threatened by habitat loss and range expansion of the Barred Owl (S. varia). An unaddressed threat is whether Barred Owls could be a source of novel strains of disease such as avian malaria (Plasmodium spp.) or other blood parasites potentially harmful for Spotted Owls. Although Barred Owls commonly harbor Plasmodium infections, these parasites have not been documented in the Spotted Owl. We screened 111 Spotted Owls, 44 Barred Owls, and 387 owls of nine other species for haemosporidian parasites (Leucocytozoon, Plasmodium, and Haemoproteus spp.). California Spotted Owls had the greatest number of simultaneous multi-species infections (44%). Additionally, sequencing results revealed that the Northern and California Spotted Owl subspecies together had the highest number of Leucocytozoon parasite lineages (n=17) and unique lineages (n=12). This high level of sequence diversity is significant because only one leucocytozoon species (L. danilewskyi) has been accepted as valid among all owls, suggesting that L. danilewskyi is a cryptic species. Furthermore, a Plasmodium parasite was documented in a Northern Spotted Owl for the first time. West Coast Barred Owls had a lower prevalence of infection (15%) when compared to sympatric Spotted Owls (S. o. caurina 52%, S. o. occidentalis 79%) and Barred Owls from the historic range (61%). Consequently, Barred Owls on the West Coast may have a competitive advantage over the potentially immune compromised Spotted Owls. ?? 2008 Ishak et al.

  9. Blood Parasites in Owls with Conservation Implications for the Spotted Owl (Strix occidentalis)

    PubMed Central

    Ishak, Heather D.; Dumbacher, John P.; Anderson, Nancy L.; Keane, John J.; Valkiūnas, Gediminas; Haig, Susan M.; Tell, Lisa A.; Sehgal, Ravinder N. M.

    2008-01-01

    The three subspecies of Spotted Owl (Northern, Strix occidentalis caurina; California, S. o. occidentalis; and Mexican, S. o. lucida) are all threatened by habitat loss and range expansion of the Barred Owl (S. varia). An unaddressed threat is whether Barred Owls could be a source of novel strains of disease such as avian malaria (Plasmodium spp.) or other blood parasites potentially harmful for Spotted Owls. Although Barred Owls commonly harbor Plasmodium infections, these parasites have not been documented in the Spotted Owl. We screened 111 Spotted Owls, 44 Barred Owls, and 387 owls of nine other species for haemosporidian parasites (Leucocytozoon, Plasmodium, and Haemoproteus spp.). California Spotted Owls had the greatest number of simultaneous multi-species infections (44%). Additionally, sequencing results revealed that the Northern and California Spotted Owl subspecies together had the highest number of Leucocytozoon parasite lineages (n = 17) and unique lineages (n = 12). This high level of sequence diversity is significant because only one Leucocytozoon species (L. danilewskyi) has been accepted as valid among all owls, suggesting that L. danilewskyi is a cryptic species. Furthermore, a Plasmodium parasite was documented in a Northern Spotted Owl for the first time. West Coast Barred Owls had a lower prevalence of infection (15%) when compared to sympatric Spotted Owls (S. o. caurina 52%, S. o. occidentalis 79%) and Barred Owls from the historic range (61%). Consequently, Barred Owls on the West Coast may have a competitive advantage over the potentially immune compromised Spotted Owls. PMID:18509541

  10. Hematozoa from the spotted owl.

    PubMed

    Gutiérrez, R J

    1989-10-01

    One hundred five spotted owls (Strix occidentalis) from seven populations and three subspecies were examined for hematozoa. Haemoproteus noctuae, H. syrnii, Leucocytozoon ziemanni, Trypanosoma avium, Atoxoplasma sp. and unidentified microfilariae were recorded. All northern (S. occidentalis caurina), California (S. occidentalis occidentalis) and Mexican (S. occidentalis lucida) spotted owls were infected with at least one hematozoan; 79% had multiple infections. Twenty-two percent of the owls were infected with as many as four species of parasites. There were significant differences in the prevalence of these species of parasites occurring among the five populations of northern and California spotted owls sampled in California. Haemoproteus noctuae, H. syrnii and Atoxoplasma sp. represented new host records for this host species.

  11. Burrowing Owls, Pulex irritans, and Plague.

    PubMed

    Belthoff, James R; Bernhardt, Scott A; Ball, Christopher L; Gregg, Michael; Johnson, David H; Ketterling, Rachel; Price, Emily; Tinker, Juliette K

    2015-09-01

    Western Burrowing Owls (Athene cunicularia hypugaea) are small, ground-dwelling owls of western North America that frequent prairie dog (Cynomys spp.) towns and other grasslands. Because they rely on rodent prey and occupy burrows once or concurrently inhabited by fossorial mammals, the owls often harbor fleas. We examined the potential role of fleas found on burrowing owls in plague dynamics by evaluating prevalence of Yersinia pestis in fleas collected from burrowing owls and in owl blood. During 2012-2013, fleas and blood were collected from burrowing owls in portions of five states with endemic plague-Idaho, Oregon, Washington, Colorado, and South Dakota. Fleas were enumerated, taxonomically identified, pooled by nest, and assayed for Y. pestis using culturing and molecular (PCR) approaches. Owl blood underwent serological analysis for plague antibodies and nested PCR for detection of Y. pestis. Of more than 4750 fleas collected from owls, Pulex irritans, a known plague vector in portions of its range, comprised more than 99.4%. However, diagnostic tests for Y. pestis of flea pools (culturing and PCR) and owl blood (PCR and serology) were negative. Thus, even though fleas were prevalent on burrowing owls and the potential for a relationship with burrowing owls as a phoretic host of infected fleas exists, we found no evidence of Y. pestis in sampled fleas or in owls that harbored them. We suggest that studies similar to those reported here during plague epizootics will be especially useful for confirming these results.

  12. Occurrence and biomagnification of organohalogen pollutants in two terrestrial predatory food chains.

    PubMed

    Yu, Lehuan; Luo, Xiaojun; Zheng, Xiaobo; Zeng, Yanhong; Chen, Da; Wu, Jiangping; Mai, Bixian

    2013-09-01

    Organohalogen pollutants (OHPs), including dichlorodiphenyl trichloroethane and its metabolites (DDTs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDs), and dechlorane plus (DP), were determined in three raptor species, namely, the common kestrel (Falco tinnunculus), eagle owl (Bubo bubo), and little owl (Athene noctua), as well as in their primary prey items: Eurasian tree sparrow (Passer montanus) and brown rat (Rattus norvegicus). DDTs were the predominant pollutants in avian species followed by PBDEs and PCBs, then minimally contribution of HBCDs and DP. Inter-species differences in the PBDE congener profiles were observed between the owls and the common kestrels, with relatively high contributions of lower brominated congeners in the owls but highly brominated congeners in the kestrels. This result may partly be attributed to a possible greater in vivo biotransformation of highly brominated BDE congeners in owls than in kestrels. α-HBCD was the predominant diastereoisomer with a preferential enrichment of (-)-enantiomer in all the samples. No stereoselective bioaccumulation was found for DP isomers in the investigated species. Biomagnification factor (BMF) values were generally higher in the rat-owl food chain than in the sparrow-kestrel food chain. Despite this food chain-specific biomagnification, the relationships between the log BMF and log KOW of PCBs and PBDEs followed a similar function in the two food chains, except for BDE-47, -99, and -100 in the sparrow-kestrel feeding relationship. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Albinism in the Great Gray Owl (Strix nebulosa) and other owls

    Treesearch

    Pentti Alaja; Heimo Mikkola

    1997-01-01

    An incomplete albino Great Gray Owl (Strix nebulosa) was observed in Vesanto and Kajaani, Finland, 1994-1995. The literature pertaining to albinism in owls indicates that total and incomplete albinism has only been reported in 13 different owl species, the Great Gray Owl being the only species with more than five records. Thus six to seven incomplete...

  14. Does the presence of barred owls suppress the calling behavior of spotted owls?

    Treesearch

    M.L. Crozier; M.E. Seamans; R.J. Gutierrez; P.J. Loschl; R.B. Horn; S.G. Sovern; E.D. Forsman

    2006-01-01

    Barred Owls (Strix varia) have expanded their range throughout the ranges of northern (Strix occidentalis caurina) and California spotted owls (S. o. occidentalis). Field observations have suggested that barred owls may be behaviorally dominant to spotted owls. Therefore, we conducted a test of behavioral...

  15. Lead and arsenic in bones of birds of prey from Spain.

    PubMed

    Mateo, R; Taggart, M; Meharg, A A

    2003-01-01

    The bones (humerus and/or femur) of 229 birds of prey from 11 species were analyzed for Pb and As to evaluate their exposure to Pb shot. The species with the highest mean Pb levels were red kite (Milvus milvus) and Eurasian griffon (Gyps fulvus), and the species with the lowest levels were Eurasian buzzard (Buteo buteo) and booted eagle (Hieraaetus pennatus). Red kite also had the highest mean As level, an element present in small amounts in Pb shot. Elevated bone Pb concentrations (>10 microg/g dry weight) were found in 10 birds from six species. Clinical signs compatible with lethal Pb poisoning and/or excessive bone Pb concentrations (>20 microg/g) were observed in one Eurasian eagle-owl (Bubo bubo), one red kite, and one Eurasian griffon. Pb poisoning has been diagnosed in eight upland raptor species in Spain to date.

  16. Rodenticides in British barn owls.

    PubMed

    Newton, I; Wyllie, I; Freestone, P

    1990-01-01

    Out of 145 Barn Owls found dead through accidents (66%), starvation (32%), shooting (2%) and poisoning (<1%), 10% contained residues of rodenticides, difenacoum or brodifacoum, in their livers. Difenacoum was in the range 0.005-0.106 microg g(-1) fresh weight, and brodifacoum was in the range 0.019-0.515 microg g(-1). Minimum levels of detection were about 0.005 microg g(-1) for both chemicals. Mice fed for 1 day on food containing difenacoum and brodifacoum died after 2-11 days. Within these mice residues were present at greater concentration in the liver than in the rest of the carcass. The mean mass of residue in a whole 35g mouse was estimated at 10.17 microg (range 4.73-20.65 microg) for difenacoum and 15.36 microg (range 8.07-26.55) for brodifacoum. Such poisoned mice were fed to Barn Owls for successive periods of 1, 3 and 6 days. All six owls fed on difenacoum-dosed mice survived all three treatments, in which up to an estimated 101.7 microg of difenacoum was consumed, and the coagulation times of their blood returned to near normal in less than 5-23 days. Four of the six owls fed on brodifacoum-dosed mice died 6-17 days after the 1-day treatment, but the survivors also survived the 3-day and 6-day treatments. Those that died had each eaten 3 mice, with a combined weight of about 105g and a total brodifacoum content of about 46.07 microg, which was equivalent to a dose of 0.150-0.182 mg kg(-1) of owl body weight. After death these owls had 0.63-1.25 micro g(-1) of brodifacoum in their livers. Blood from the survivors would not coagulate at 9 days post-treatment, but did so at 16 days in one bird and between 38 and 78 days in the other. It is concluded that: (1) Barn Owls in Britain are now widely exposed to second-generation rodenticides; (2) not all owls exposed to these chemicals are likely to receive a lethal dose; (3) brodifacoum is more toxic to owls than difenacoum; and (4) while there is yet no evidence that rodenticides have had any appreciable

  17. Aerobic bacterial flora of addled raptor eggs in Saskatchewan.

    PubMed

    Houston, C S; Saunders, J R; Crawford, R D

    1997-04-01

    In south-central Saskatchewan, Canada, in 1986, 1987 and 1989, the aerobic bacterial flora was evaluated from 75 unhatched raptor eggs of three species: 42 of the Swainson's hawk (Buteo Swainsoni), 21 of the ferruginous hawk (Buteo regalis), and 12 of the great horned owl (Bubo virginianus). In addled Swainson's hawk eggs, the most common bacterial genera were Enterobacter (18 eggs), Escherichia (12), and Streptococcus (10). Seven great horned owl eggs and six ferruginous hawk eggs also contained Escherichia coli. Salmonella spp. were not isolated. These bacteria were interpreted as secondary contaminants and not the primary cause of reproductive failure.

  18. Environmental factors associated with spotted owl reproduction

    Treesearch

    Malcolm P. North

    2002-01-01

    Although research on spotted owls (Strix occidentalis) has increased dramatically in the last decade, factors influencing owl reproduction still are poorly known. This ongoing study uses 9 years of demographic data to analyze associations between owl reproduction and weather, cone crop abundance, and nest-site structure. Initial results indicate no...

  19. Chapter 17. Information needs: Great gray owls

    Treesearch

    Gregory D. Hayward

    1994-01-01

    Current understanding of great gray owl biology and ecology is based on studies of less than five populations. In an ideal world, a strong conservation strategy would require significant new information. However, current knowledge suggests that conservation of this forest owl should involve fewer conflicts than either the boreal or flammulated owl. The mix of forest...

  20. The biology of the California spotted owl

    Treesearch

    R.J. Gutiérrez; Douglas J. Tempel; M. Zachariah Peery

    2017-01-01

    The spotted owl (Strix occidentalis) is one of the most studied raptors in the world (Lõmus 2004) because forest management throughout its range has the potential to negatively affect owl populations. Information on the California spotted owl (S. o. occidentalis) has been summarized in several literature reviews (e.g.,...

  1. Owls of old forests of the world.

    Treesearch

    Bruce G. Marcot

    1995-01-01

    A review of literature on habitat associations of owls of the world revealed that about 83 species of owls among 18 genera are known or suspected to be closely associated with old forests. Old forest is defined as old-growth or undisturbed forests, typically with dense canopies. The 83 owl species include 70 tropical and 13 temperate forms. Specific habitat...

  2. Survey of blood parasites in two forest owls, Northern Saw-whet Owls and Flammulated Owls, of western North America.

    PubMed

    Leppert, Lynda L; Dufty, Alfred M; Stock, Sarah; Oleyar, M David; Kaltenecker, Greg S

    2008-04-01

    Except for a few studies in the eastern United States, little has been published on hemoparasites in owls. We surveyed the blood parasites of 108 Northern Saw-whet Owls (Aegolius acadicus) and 24 Flammulated Owls (Otus flammeolus) in Idaho during autumn migration in 1999 and 2000. We also surveyed 15 Flammulated Owls (FLOW) during breeding season in Utah from 2000. Leucocytozoon ziemanni, Haemoproteus syrnii, Haemoproteus noctuae, and Trypanosoma avium were identified. The overall prevalence of infection was 53% (78/147) and for the combined species, prevalences of Haemoproteus, Leucocytozoon, and Trypanosoma species were 20%, 39%, and 4%, respectively. Northern Saw-whet Owls (NSWO) had an overall prevalence of 51% (55/108), with prevalences of 6%, 47%, and 4% by hemoparasite genus, respectively. Flammulated Owls had an overall prevalence of 59% (23/39), with prevalences of 56%, 18%, and 5% by genus, respectively. This study provides baseline hematozoa information for two boreal owl species.

  3. Dead simple OWL design patterns.

    PubMed

    Osumi-Sutherland, David; Courtot, Melanie; Balhoff, James P; Mungall, Christopher

    2017-06-05

    Bio-ontologies typically require multiple axes of classification to support the needs of their users. Development of such ontologies can only be made scalable and sustainable by the use of inference to automate classification via consistent patterns of axiomatization. Many bio-ontologies originating in OBO or OWL follow this approach. These patterns need to be documented in a form that requires minimal expertise to understand and edit and that can be validated and applied using any of the various programmatic approaches to working with OWL ontologies. Here we describe a system, Dead Simple OWL Design Patterns (DOS-DPs), which fulfills these requirements, illustrating the system with examples from the Gene Ontology. The rapid adoption of DOS-DPs by multiple ontology development projects illustrates both the ease-of use and the pressing need for the simple design pattern system we have developed.

  4. Dead simple OWL design patterns

    DOE PAGES

    Osumi-Sutherland, David; Courtot, Melanie; Balhoff, James P.; ...

    2017-06-05

    Bio-ontologies typically require multiple axes of classification to support the needs of their users. Development of such ontologies can only be made scalable and sustainable by the use of inference to automate classification via consistent patterns of axiomatization. Many bio-ontologies originating in OBO or OWL follow this approach. These patterns need to be documented in a form that requires minimal expertise to understand and edit and that can be validated and applied using any of the various programmatic approaches to working with OWL ontologies. We describe a system, Dead Simple OWL Design Patterns (DOS-DPs), which fulfills these requirements, illustrating themore » system with examples from the Gene Ontology. In conclusion, the rapid adoption of DOS-DPs by multiple ontology development projects illustrates both the ease-of use and the pressing need for the simple design pattern system we have developed.« less

  5. Barred owls and landscape attributes influence territory occupancy of northern spotted owls.

    PubMed

    Sovern, Stan G; Forsman, Eric D; Olson, Gail S; Biswell, Brian L; Taylor, Margaret; Anthony, Robert G

    2014-11-01

    We used multi-season occupancy analyses to model 2 fates of northern spotted owl territories in relation to habitat amount, habitat fragmentation, and the presence of barred owls in Washington State, USA, 1989-2005. Local colonization is the probability a territory unoccupied by a spotted owl in year i would be occupied in year i + 1, and local extinction is the probability a territory that was occupied by a spotted owl in year i would be unoccupied in year i + 1. We found a negative relationship between local extinction probability and amount of late-seral forest edge. We found a negative relationship between colonization probability and the number of late-seral forest patches (higher fragmentation), and a negative relationship between colonization probability and the amount of non-habitat within 600 m of a spotted owl territory center (Akaike weight = 0.59). The presence of barred owls was positively related to extinction probability and negatively related to detection probability of spotted owls. The negative relationship between presence of barred owls and detectability of spotted owls indicated that spotted owls could be modifying their calling behavior in the presence of barred owls. The positive relationship between barred owl detections and local extinction probability suggests that because of competition with barred owls, spotted owls are being displaced. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

  6. Comparative ecology of the Flammulated Owl and Northern Saw-whet Owl during fall migration

    USGS Publications Warehouse

    Stock, S.L.; Heglund, P.J.; Kaltenecker, G.S.; Carlisle, J.D.; Leppert, L.

    2006-01-01

    We compared the migration ecology of two owl species that exhibit different migration strategies: the Flammulated Owl (Otus flammeolus) and the Northern Saw-whet Owl (Aegolius acadicus). During fall 1999-2004, we captured 117 Flammulated Owls and 1433 Northern Saw-whet Owls in the southern Boise Mountains of southwestern Idaho. These owl species exhibited contrasting seasonal timing and body condition. Flammulated Owl captures peaked in mid-September and Northern Saw-whet Owl captures peaked in early to mid-October. Flammulated Owls displayed greater body condition than Northern Saw-whet Owls and increasing condition scores during the season, whereas Northern Saw-whet Owls had no apparent seasonal condition patterns. Based on seasonal timing of captures, both species showed unimodal movement patterns characteristic of fall migrants. However, in 1999 both species' capture rates were at least double those in other years of this study. Flammulated Owls' earlier arrival and departure, coupled with superior body condition, were consistent among years and typical of a long-distance migration strategy. In contrast, the Northern Saw-whet Owls' later arrival, more lengthy passage, and variable body condition were more characteristic of a short-distance migrant strategy. Furthermore, Northern Saw-whet Owls' body condition was significantly lower during the irruptive year than during nonirruptive years, supporting the notion that population density affects their migratory condition. ?? 2006 The Raptor Research Foundation, Inc.

  7. Barred owls and landscape attributes influence territory occupancy of northern spotted owls

    PubMed Central

    Sovern, Stan G; Forsman, Eric D; Olson, Gail S; Biswell, Brian L; Taylor, Margaret; Anthony, Robert G

    2014-01-01

    We used multi-season occupancy analyses to model 2 fates of northern spotted owl territories in relation to habitat amount, habitat fragmentation, and the presence of barred owls in Washington State, USA, 1989–2005. Local colonization is the probability a territory unoccupied by a spotted owl in year i would be occupied in year i + 1, and local extinction is the probability a territory that was occupied by a spotted owl in year i would be unoccupied in year i + 1. We found a negative relationship between local extinction probability and amount of late-seral forest edge. We found a negative relationship between colonization probability and the number of late-seral forest patches (higher fragmentation), and a negative relationship between colonization probability and the amount of non-habitat within 600 m of a spotted owl territory center (Akaike weight = 0.59). The presence of barred owls was positively related to extinction probability and negatively related to detection probability of spotted owls. The negative relationship between presence of barred owls and detectability of spotted owls indicated that spotted owls could be modifying their calling behavior in the presence of barred owls. The positive relationship between barred owl detections and local extinction probability suggests that because of competition with barred owls, spotted owls are being displaced. Published 2014. This article is a U.S. Government work and is in the public domain in the USA. PMID:25558093

  8. Vernier acuity in barn owls.

    PubMed

    Harmening, Wolf M; Göbbels, Katrin; Wagner, Hermann

    2007-03-01

    Vernier acuity thresholds were obtained psychophysically in three adult barn owls with vertical bars and sinusoidal gratings. A minimal displacement threshold of 0.58 arcmin was observed with the bar stimulus under binocular viewing conditions. The mean binocular bar threshold was 2.51 arcmin. Bar thresholds were lower than grating thresholds. Monocular thresholds, obtained in one bird only, were typically higher than binocular thresholds. With grating acuity being about 3.75 arcmin in this species, we conclude that the findings reported here indicate that vernier acuity is hyperacute in the barn owl. The data presented here are the first demonstration of vernier acuity thresholds in birds.

  9. Avian pox in eastern screech owls and barred owls from Florida.

    PubMed

    Deern, S L; Heard, D J; Fox, J H

    1997-04-01

    Avian pox was diagnosed in two eastern screech owls (Otus asio) and two barred owls (Strix, varia) living in different regions of Florida (USA) between November 1994 and October 1995. Avian poxvirus infection was confirmed by the presence of eosinophilic intracytoplasmic epidermal inclusions (Bollinger bodies) on light microscopy of tissue from all four owls. Additionally, typical poxvirus particles were demonstrated by electron microscopy of a lesion from one of the eastern screech owls. These are the first published case reports of avian pox in eastern screech owls and barred owls.

  10. Role of prey and intraspecific density dependence on the population growth of an avian top predator

    NASA Astrophysics Data System (ADS)

    Fernandez-de-Simon, Javier; Díaz-Ruiz, Francisco; Cirilli, Francesca; Tortosa, Francisco S.; Villafuerte, Rafael; Ferreras, Pablo

    2014-10-01

    Exploring predator-prey systems in diverse ecosystems increases our knowledge about ecological processes. Predator population growth may be positive when conspecific density is low but predators also need areas with prey availability, associated with competition, which increases the risk of suffering losses but stabilises populations. We studied relationships between European rabbits Oryctolagus cuniculus (prey) and adult eagle owls Bubo bubo (predators) in south-western Europe. We assessed models explaining the predator population growth and stability. We estimated the abundance of rabbits and adult eagle owls during three years in eight localities of central-southern Spain. We explored models including rabbit and adult eagle owl abundance, accounting for yearly variations and including the locality as a random variable. We found that population growth of adult eagle owls was positive in situations with low conspecific abundance and tended to be negative but approaching equilibrium in situations of higher conspecific abundance. Population growth was also positively related to previous summer rabbit density when taking into account eagle owl conspecific abundance, possibly indicating that rabbits may support recruitment. Furthermore, abundance stability of adult eagle owls was positively related to previous winter-spring rabbit density, which could suggest predator population stabilisation through quick territory occupation in high-quality areas. These results exemplify the trade-off between prey availability and abundance of adult predators related to population growth and abundance stability in the eagle owl-rabbit system in south-western Europe. Despite rabbits have greatly declined during the last decades and eagle owls locally specialise on them, eagle owls currently have a favourable conservation status. As eagle owls are the only nocturnal raptor with such dependence on rabbits, this could point out that predators may overcome prey decreases in areas with

  11. Chapter 5: California spotted owls

    Treesearch

    S. Roberts; M. North

    2012-01-01

    California spotted owls (Strix occidentalis occidentalis) are habitat specialists that are strongly associated with late-successional forests. For nesting and roosting, they require large trees and snags embedded in a stand with a complex forest structure (Blakesley et al. 2005, Gutiérrez et al. 1992, Verner et al. 1992b). In...

  12. Transient dynamics of invasive competition: barred owls, spotted owls, habitat, and the demons of competition present.

    PubMed

    Dugger, Katie M; Anthony, Robert G; Andrews, Lawrence S

    2011-10-01

    The recent range expansion of Barred Owls (Strix varia) into the Pacific Northwest, where the species now co-occurs with the endemic Northern Spotted Owl (Strix occidentalis caurina), resulted in a unique opportunity to investigate potential competition between two congeneric, previously allopatric species. The primary criticism of early competition research was the use of current species' distribution patterns to infer past processes; however, the recent expansion of the Barred Owl and the ability to model the processes that result in site occupancy (i.e., colonization and extinction) allowed us to address the competitive process directly rather than inferring past processes through current patterns. The purpose of our study was to determine whether Barred Owls had any negative effects on occupancy dynamics of nesting territories by Northern Spotted Owls and how these effects were influenced by habitat characteristics of Spotted Owl territories. We used single-species, multi-season occupancy models and covariates quantifying Barred Owl detections and habitat characteristics to model extinction and colonization rates of Spotted Owl pairs in southern Oregon, USA. We observed a strong, negative association between Barred Owl detections and colonization rates and a strong positive effect of Barred Owl detections on extinction rates of Spotted Owls. We observed increased extinction rates in response to decreased amounts of old forest at the territory core and higher colonization rates when old-forest habitat was less fragmented. Annual site occupancy for pairs reflected the strong effects of Barred Owls on occupancy dynamics with much lower occupancy rates predicted for territories where Barred Owls were detected. The strong Barred Owl and habitat effects on occupancy dynamics of Spotted Owls provided evidence of interference competition between the species. These effects increase the importance of conserving large amounts of contiguous, old-forest habitat to maintain

  13. Range expansion of Northern Hawk Owls (Surnia ulula) and Boreal Owls (Aegolius funereus) in Nova Scotia

    Treesearch

    Randy F. Lauff

    1997-01-01

    The Northern Hawk Owl (Surnia ulula) has never been recorded to breed in Nova Scotia (and only once in recent history in all of the Maritimes). Three pairs of hawk owls were found within 4 km² of woods in 1996, and of these, young were found with two pairs. The first provincial summer record for the Boreal Owl (Aegolius funereus...

  14. Barred owl occupancy surveys within the range of the northern spotted owl

    Treesearch

    J. David Wiens; Robert G. Anthony; Eric D. Forsman

    2011-01-01

    The range expansion by barred owls (Strix varia) into western North America has raised considerable concern regarding their potential effects on declining northern spotted owl (Strix occidentalis caurina) populations, yet most information on the occurrence of barred owls in the region is limited to incidental detections during...

  15. 78 FR 44588 - Experimental Removal of Barred Owls To Benefit Threatened Northern Spotted Owls; Final...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-24

    ... threatened northern spotted owls. The barred owl, a species recently established in western North America, is... management tool. The action alternatives vary by the number and location of study areas, the type of... under the Endangered Species Act (16 U.S.C. 1531 et seq.; Act). Competition from barred owls (Strix...

  16. A baby owl is found at CCAFS

    NASA Technical Reports Server (NTRS)

    2000-01-01

    A baby owl, possibly a screech owl, stares at the photographer snapping its picture. The owl was found on the stairs inside Hangar G, Cape Canaveral Air Force Station. It had apparently tried to fly from a nest near the ceiling but couldn't get back to it. Workers called an Audubon rescue center near Orlando, which captured it and will ensure the bird is returned to the wild when it's ready.

  17. A baby owl is found at CCAFS

    NASA Technical Reports Server (NTRS)

    2000-01-01

    A baby owl, possibly a screech owl, displays its wings at the photographer snapping its picture. The owl was found on the stairs inside Hangar G, Cape Canaveral Air Force Station. It had apparently tried to fly from a nest near the ceiling but couldn't get back to it. Workers called an Audubon rescue center near Orlando, which captured it and will ensure the bird is returned to the wild when it's ready.

  18. A baby owl is found at CCAFS

    NASA Technical Reports Server (NTRS)

    2000-01-01

    A baby owl, possibly a screech owl, shows its fear and resentment of the photographer snapping its picture. The owl was found on the stairs inside Hangar G, Cape Canaveral Air Force Station. It had apparently tried to fly from a nest near the ceiling but couldn't get back to it. Workers called an Audubon rescue center near Orlando, which captured it and will ensure the bird is returned to the wild when it's ready.

  19. Secondary poisoning of owls by anticoagulant rodenticides

    USGS Publications Warehouse

    Mendenhall, V.M.; Pank, L.F.

    1980-01-01

    Anticoagulants-compounds that prevent clotting of the blood-are extensively used for control of small mammal pests. The potential secondary hazards of 6 anticoagulant rodenticides to birds of prey were examined in this study. Whole rats or mice were killed with each anticoagulant and were fed to 1-3 species of owls. Owls died of hemorrhaging after feeding on rats killed with bromadiolone, brodifacoum, or diphacinone; sublethal hemorrhaging occurred in owls fed rats killed with difenacoum. These results demonstrate potential secondary hazards of 4 anticoagulants to avian predators. No abnormalities were observed in owls fed rats killed with fumarin and chlorophacinone

  20. Noninvasive measures of reproductive function and disturbance in the barred owl, great horned owl, and northern spotted owl.

    PubMed

    Wasser, Samuel K; Hunt, Kathleen E

    2005-06-01

    There is an urgent need for noninvasive methods to study reproduction and environmental stress in at-risk species such as the northern spotted owl (Strix occidentalis caurina). Two related owl species (barred owl and great horned owl) were used as surrogates to validate hormone assays for fecal metabolites of progesterone, 17beta-estradiol, testosterone, and corticosterone. Infusions of radiolabeled hormones showed that the owls excreted most hormone within 6 h. Feces and urine contained roughly equal amounts of hormone, and most fecal hormone metabolites were quite polar. The testosterone and corticosterone assays in this study bound to the major excreted metabolites of these hormones, but two progesterone assays did not appreciably bind to the major progesterone metabolites. All assays showed excellent parallelism with hydrolyzed and unhydrolyzed samples and with previously dried or undried fecal samples. Thus, samples do not require hydrolysis or prior drying. Samples from a female barred owl had significantly higher fecal estrogen, lower fecal testosterone, and higher fecal estrogen/testosterone ratio than samples from two male barred owls. The fecal estrogen/testosterone ratio was the most accurate predictor of owl gender, particularly if two or more samples are available from the same individual. Fecal corticosterone metabolites also demonstrated considerable utility for wild northern spotted owls. Fecal glucocorticoid levels varied by gender and breeding stage, being highest in male northern spotted owls early in the breeding season and highest in females when nestlings were fledging. Collectively, these studies show that noninvasive fecal hormone measurements show great promise for noninvasive assessment of reproduction and stress in wild owls.

  1. Competitive interactions and resource partitioning between northern spotted owls and barred owls in western Oregon

    USGS Publications Warehouse

    Wiens, J. David; Anthony, Robert G.; Forsman, Eric D.

    2014-01-01

    The federally threatened northern spotted owl (Strix occidentalis caurina) is the focus of intensive conservation efforts that have led to much forested land being reserved as habitat for the owl and associated wildlife species throughout the Pacific Northwest of the United States. Recently, however, a relatively new threat to spotted owls has emerged in the form of an invasive competitor: the congeneric barred owl (S. varia). As barred owls have rapidly expanded their populations into the entire range of the northern spotted owl, mounting evidence indicates that they are displacing, hybridizing with, and even killing spotted owls. The range expansion by barred owls into western North America has made an already complex conservation issue even more contentious, and a lack of information on the ecological relationships between the 2 species has hampered recovery efforts for northern spotted owls. We investigated spatial relationships, habitat use, diets, survival, and reproduction of sympatric spotted owls and barred owls in western Oregon, USA, during 2007–2009. Our overall objective was to determine the potential for and possible consequences of competition for space, habitat, and food between these previously allopatric owl species. Our study included 29 spotted owls and 28 barred owls that were radio-marked in 36 neighboring territories and monitored over a 24-month period. Based on repeated surveys of both species, the number of territories occupied by pairs of barred owls in the 745-km2 study area (82) greatly outnumbered those occupied by pairs of spotted owls (15). Estimates of mean size of home ranges and core-use areas of spotted owls (1,843 ha and 305 ha, respectively) were 2–4 times larger than those of barred owls (581 ha and 188 ha, respectively). Individual spotted and barred owls in adjacent territories often had overlapping home ranges, but interspecific space sharing was largely restricted to broader foraging areas in the home range

  2. Environmental exposure and distribution of lead in four species of raptors in Southeastern Spain.

    PubMed

    García-Fernández, A J; Motas-Guzmán, M; Navas, I; María-Mojica, P; Luna, A; Sánchez-García, J A

    1997-07-01

    The purpose of this study was to monitor exposure to lead in four species of raptors in Southeastern Spain (Murcia Region). Samples of liver, kidney, brain, blood, and bone from two species of diurnal raptors (European kestrel (Falco tinnunculus) and European buzzard (Buteo buteo)) and two species of nocturnal raptors (Eagle owl (Bubo bubo) and Little owl (Athene noctua)) were obtained during 1994. Relationships were found between size and age of the birds, the nearness to areas of human activity and lead concentrations in tissues. The lead distribution pattern reveals that the bone is the principle organ for accumulation (0.62-43 mg/Kg, dry weight), followed by the kidney (0.03-0.66 mg/Kg, wet weight), and liver (0. 017-0.05 mg/Kg, w.w.), and to lesser extent, the brain (0.013-0.223 mg/Kg, w.w.). This distribution pattern indicates that raptors in Southeastern Spain were exposed to environmental low lead levels continuously over an extended period of time. Correlations between lead in bone and lead in soft tissues were higher in European buzzards (r = 0.87-0.95) and Eagle owl (r = 0.71-0.86) than those found in European kestrels (r = 0.53-0.58) and Little owls (r < 0). However, correlations between lead concentrations in soft tissues and in blood were high (r = 0.85-0.99).

  3. The occurrence of second generation anticoagulant rodenticides in non-target raptor species in Norway.

    PubMed

    Langford, Katherine H; Reid, Malcolm; Thomas, Kevin V

    2013-04-15

    Second generation anticoagulant rodenticides (SGARs) are commonly used for rodent pest control in Norway resulting in the potential exposure of non-target raptor species. In this study the occurrence of flocoumafen, difethialone, difenacoum, bromadiolone and brodifacoum was determined in the livers of five species of raptors found dead in Norway between 2009 and 2011. The SGARs brodifacoum, bromadiolone, difenacoum and flocoumafen were detected in golden eagle (Aquila chrysaetos) and eagle owl (Bubo bubo) livers at a total SGAR concentration of between 11 and 255 ng/g in approximately 70% of the golden eagles and 50% of the eagle owls examined in this study. In the absence of specific golden eagle and eagle owl toxicity thresholds for SGARs, a level of >100 ng/g was used as a potential lethal range, accepting that poisoning may occur below this level. Thirty percent (7/24) of the golden eagle and eagle owl livers contained total SGAR residue levels above this threshold. Further estimation of the potential mortality impact on the sampled raptor populations was not possible. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. Protein electrophoresis as a diagnostic and prognostic tool in raptor medicine.

    PubMed

    Tatum, L M; Zaias, J; Mealey, B K; Cray, C; Bossart, G D

    2000-12-01

    Plasma proteins of 139 healthy adult birds of prey from 10 species were separated by electrophoresis to characterize and document normal reference ranges and species-specific electrophoretic patternsand to evaluate the value of this technique for health screening, disease diagnosis, and prognostic indication. Species studied included bald eagle (Haliaeetus leucocephalus), red-tailed hawk (Buteo jamaicensis), barn owl (Tyto alba), great horned owl (Bubo virginianus), turkey vulture (Cathartes aura), Harris' hawk (Parabuteo unicinctus), Stellar's sea eagle (Haliaeetus pelagicus), barred owl (Strix varia), screech owl (Otus asio), and black vulture (Coragyps atratus). Several clinical cases show the diagnostic/therapeutic value of protein electrophoresis in raptors. This study establishes species-specific reference ranges for several birds of prey and discusses the benefit of electrophoresis as a diagnostic technique in health screens, as a diagnostic aid in conjunction with other tests, and as a prognostic indicator in clinical evaluation of raptors.

  5. Ecology of the great gray owl.

    Treesearch

    Evelyn L. Bull; Mark G. Henjum

    1990-01-01

    Information is needed on the great gray owl to understand its ecology and to consider this species in land management decisions. From 1982 to 1988, we studied 24 pairs and 107 juvenile great gray owls in northeastern Oregon. Forty-nine nests were located; 16 were used more than once, so we observed 71 nesting attempts. Seventy-eight percent of these nesting attempts...

  6. Annual weight cycle in wild screech owls

    USGS Publications Warehouse

    Henny, Charles J.; VanCamp, Laurel F.

    1979-01-01

    The annual weight cycle of wild birds of prey has received little attention in the past, primarily because of the difficulty in capturing and recapturing them. Screech Owls (Otus asio) are resident in our northern Ohio study area and readily occupy nest boxes established for Wood Ducks (Aix sponsa) (see VanCamp and Henny 1975). In addition to nesting in the boxes, the owls use them as roosting and feeding stations during the winter and are easily captured in the boxes during the day. Therefore, the owls presented an unusual opportunity to obtain information on their annual weight cycle.Between January 1975 and December 1978, Screech Owls were captured, weighed, and banded. Several were subsequently recaptured and weighed again to form the basis of this report. It is difficult to sex live Screech Owls in the field because they are not sexually dimorphic; however, Sherman (1911) noted that females did all of the incubating. We sexed adult owls with young at nest sites by the presence (female) or absence (male) of a brood patch. Owls captured away from nests during the nesting season without brood patches, or at other times of the year, were classified as sex unknown, unless they were previously captured at a nest with young. Screech Owls in northern Ohio have young in the nests from mid-April through early June.

  7. What Do Great Horned Owls Eat?

    ERIC Educational Resources Information Center

    Bandelier, Kenneth J.

    1993-01-01

    Presents an activity to determine the identity of animals that owls ingest. Students dissect and examine the contents of "owl pellets" which are the indigestible parts of animals that are regurgitated after eating. Provides instructions for implementing and extending the activity. (MDH)

  8. California spotted owl habitat characteristics and use

    Treesearch

    Susan L. Roberts

    2017-01-01

    California spotted owls (Strix occidentalis occidentalis) establish large home ranges averaging about 1279 ha (3,160 ac) (table 3-1), and within these home ranges individual owls select habitat at different scales, depending on their activity. At the smallest spatial scale, the nest tree, it appears there is very limited flexibility in the...

  9. Chapter 3. Current management situation: Flammulated owls

    Treesearch

    Jon Verner

    1994-01-01

    The flammulated owl (Otus flammeolus) is a western mountain species associated mainly with ponderosa (Pinus ponderosa) and Jeffrey pine (Pinus jefferyi) forests in the United States and Canada (see Chapter 4). As a neotropical migrant, this small forest owl occurs on national forests in the United States during...

  10. Chapter 8. Current management situation: Boreal owls

    Treesearch

    Jon Verner

    1994-01-01

    The range of boreal owls (Aegolius funereus) in the United States includes Alaska, the mountains of the western United States, and the northern tier states from the Atlantic to Pacific (see Chapter 9). Based on the species' documented distribution (see National Geographic Society 1987, Hayward et al. 1987, Johnsgard 1988, and others) the owl may...

  11. What Do Great Horned Owls Eat?

    ERIC Educational Resources Information Center

    Bandelier, Kenneth J.

    1993-01-01

    Presents an activity to determine the identity of animals that owls ingest. Students dissect and examine the contents of "owl pellets" which are the indigestible parts of animals that are regurgitated after eating. Provides instructions for implementing and extending the activity. (MDH)

  12. Size, dimorphism, and related characteristics of Ciccaba owls from Guatemala

    Treesearch

    Richard P. Gerhardt; Dawn McAnnis Gerhardt

    1997-01-01

    Tropical owls, being poorly studied, have been excluded from discussions of reversed size dimorphism. As part of a breeding and food habits study, we weighed and measured 20 Mottled Owls (Ciccaba virgata) and a mated pair of Black-and-white Owls (C. nigrolineata) in northern Guatemala. Mottled Owls exhibited pronounced dimorphism...

  13. Distribution and habitat use of Mexican Spotted Owls in Arizona

    Treesearch

    Joseph L. Ganey; Russell P. Balda

    1989-01-01

    Distribution and habitat use of Mexican Spotted Owls (Strix occidentalis lucida) in Arizona were studied from 1984-1988. Owls were widely but patchily distributed throughout the state except for the arid southwestern portion. Distribution of the owl corresponded with distribution of forested mountains and canyonlands within the state. Owls occurred...

  14. Connect Them Bones! An Interdisciplinary Study of Owl Pellets.

    ERIC Educational Resources Information Center

    Zipko, Stephen J.

    1983-01-01

    Discusses a field/laboratory study of the barn owl in which students collect and dissect owl pellets. Interdisciplinary lessons focus on eco-politics, reconstruction of owl prey skeletons, studies of predator-prey relationships, and construction/installation of nest boxes for owls and other birds. The unit begins and ends with an attitude…

  15. Connect Them Bones! An Interdisciplinary Study of Owl Pellets.

    ERIC Educational Resources Information Center

    Zipko, Stephen J.

    1983-01-01

    Discusses a field/laboratory study of the barn owl in which students collect and dissect owl pellets. Interdisciplinary lessons focus on eco-politics, reconstruction of owl prey skeletons, studies of predator-prey relationships, and construction/installation of nest boxes for owls and other birds. The unit begins and ends with an attitude…

  16. Microsatellite markers characterized in the barn owl (Tyto alba) and of high utility in other owls (Strigiformes: AVES).

    PubMed

    Klein, Akos; Horsburgh, Gavin J; Küpper, Clemens; Major, Agnes; Lee, Patricia L M; Hoffmann, Gyula; Mátics, Róbert; Dawson, Deborah A

    2009-11-01

    We have identified 15 polymorphic microsatellite loci for the barn owl (Tyto alba), five from testing published owl loci and 10 from testing non-owl loci, including loci known to be of high utility in passerines and shorebirds. All 15 loci were sequenced in barn owl, and new primer sets were designed for eight loci. The 15 polymorphic loci displayed two to 26 alleles in 56-58 barn owls. When tested in 10 other owl species (n = 1-6 individuals), between four and nine loci were polymorphic per species. These loci are suitable for studies of population structure and parentage in owls. © 2009 Blackwell Publishing Ltd.

  17. OWL references in ORM conceptual modelling

    NASA Astrophysics Data System (ADS)

    Matula, Jiri; Belunek, Roman; Hunka, Frantisek

    2017-07-01

    Object Role Modelling methodology is the fact-based type of conceptual modelling. The aim of the paper is to emphasize a close connection to OWL documents and its possible mutual cooperation. The definition of entities or domain values is an indispensable part of the conceptual schema design procedure defined by the ORM methodology. Many of these entities are already defined in OWL documents. Therefore, it is not necessary to declare entities again, whereas it is possible to utilize references from OWL documents during modelling of information systems.

  18. Formal analysis of ORM using OWL DL

    NASA Astrophysics Data System (ADS)

    Pan, Wen-lin; Liu, Da-xin

    2012-01-01

    ORM (Object Role Modeling), current version is 2.0, is a fully communication oriented information modeling method. Currently, ORM has been used in ontology engineering to model domain ontologies. To ensure the semantics of ORM model is consistent, it needs using reasoning engines to check semantic conflicts and redundancy. Furthermore, only publish ORM domain ontologies on the Semantic Web described by OWL can it is shared by different applications. Therefore, it needs to map ORM models into OWL DL. Several methods to transform ORM models have been considered and a series of general OWL DL formalization rules have been proposed.

  19. Formal analysis of ORM using OWL DL

    NASA Astrophysics Data System (ADS)

    Pan, Wen-Lin; Liu, Da-Xin

    2011-12-01

    ORM (Object Role Modeling), current version is 2.0, is a fully communication oriented information modeling method. Currently, ORM has been used in ontology engineering to model domain ontologies. To ensure the semantics of ORM model is consistent, it needs using reasoning engines to check semantic conflicts and redundancy. Furthermore, only publish ORM domain ontologies on the Semantic Web described by OWL can it is shared by different applications. Therefore, it needs to map ORM models into OWL DL. Several methods to transform ORM models have been considered and a series of general OWL DL formalization rules have been proposed.

  20. Mycobacterium avium subsp. avium found in raptors exposed to infected domestic fowl.

    PubMed

    Kriz, Petr; Kaevska, Marija; Bartejsova, Iva; Pavlik, Ivo

    2013-09-01

    We report a case of a falcon breeding facility, where raptors (both diurnal and nocturnal) were raised in contact with domestic fowl (Gallus gallus f. domesticus) infected by Mycobacterium avium subsp. avium. Fecal and environmental samples from 20 raptors and four common ravens (Corvus corax) were collected. Mycobacterium a. avium DNA was detected in feces of four raptors (bald eagle [Haliaeetus leucocephalus], eagle owl [Bubo bubo], barn owl [Tyto alba], and little owl [Athene noctua]) using triplex quantitative real-time PCR. As both the flock of domestic fowl and one of the infected raptors had the same origin (zoological collection), they might have had a common source of colonization/infection. However, the detection of M. a. avium in feces of three other raptors may point at transmission of the agent between the birds in the facility. Contact of raptors with domestic fowl infected by M. a. avium may pose a risk for transmission of the infection for them; however, raptors from the falcon breeding facility seemed to be relatively resistant to the infection.

  1. Assessment of Trace Element Concentrations in Birds of Prey in Korea.

    PubMed

    Kim, Jungsoo; Oh, Jong-Min

    2016-07-01

    This study presents liver concentrations of trace elements of cinereous vultures (Aegypius monachus), common buzzards (Buteo buteo), common kestrels (Falco tinnunculus), and Eurasian eagle owls (Bubo bubo) collected in Korea from 2007 to 2008. Iron (Fe), manganese (Mn), copper (Cu), lead (Pb), and cadmium (Cd) concentrations in common kestrel juveniles were greater than in other juveniles of birds of prey. Adult cinereous vultures had greater Fe, Pb, and Cd concentrations than in those of other species, but common kestrels had greater Mn and Cu concentrations than in those of other birds of prey. Zinc concentrations in Eurasian eagle owl juveniles and adults were greater than in juveniles and adults of other species, respectively. In common kestrels, Fe, Cu, Pb, and Cd concentrations were significantly greater in adults than in juveniles. In Eurasian eagle owls, only Pb concentrations were greater in adults than in juveniles. Essential elements, such as Fe, Zn, Mn, and Cu concentrations, were within the range of other birds of prey studies. Seventeen individual birds of prey (30 %) were at a level considered Pb exposed (6-30 µg/g dw). This is a greater proportion than reported earlier in herons, egrets, and other birds from Korea. Elevated Pb concentration might be attributed to ingestion of Pb shot and bullet fragments for cinereous vultures and common buzzards, and urbanization for common kestrels. Cadmium concentrations in birds of prey were within the background concentrations (<3 µg/g dw) for wild birds.

  2. Embryonic and neonatal mortality from salmonellosis in captive bred raptors.

    PubMed

    Battisti, A; Di Guardo, G; Agrimi, U; Bozzano, A I

    1998-01-01

    In a captive breeding center near Rome (Italy), cases of embryonic and neonatal death were recorded during the breeding seasons in the European eagle owl (Bubo bubo), peregrine falcon (Falco peregrinus), buzzard (Buteo buteo), and lanner falcon. (Falco biarmicus). Salmonella havana and S. virchow were isolated. Three pulli, clinically infected with S. havana, were successfully treated with enrofloxacin. From two groups of healthy 3- to 4-wk-old eagle owls, Salmonella sp. group 61 (61:r:-) and S. havana were collected. A strain of S. paratyphi B was detected in a pharyngeal swab and a fecal sample from an adult female goshawk (Accipiter gentilis), affected with pharyngeal trichomoniasis. A S. hadar strain was collected from a healthy 1-yr-old female eagle owl and S. livingstone was isolated from a 1-mo-old female peregrine, dead of an acute respiratory syndrome. Lesions of fibrinous polyserositis and multivisceral congestion were observed. From frozen 1-day-old chicks, on which adult and young raptors were fed, S. havana and S. livingstone isolates with similar biochemical and drug susceptibility patterns to those isolated from raptors were identified. A surveillance program on infectious diseases reduced embryonic and neonatal death rates in the following breeding seasons.

  3. The vestibular system of the owl

    NASA Technical Reports Server (NTRS)

    Money, K. E.; Correia, M. J.

    1973-01-01

    Five owls were given vestibular examinations, and two of them were sacrificed to provide serial histological sections of the temporal bones. The owls exhibited a curious variability in the postrotatory head nystagmus following abrupt deceleration; sometimes a brisk nystagnus with direction opposite to that appropriate to the stimulus would occur promptly after deceleration. It was found also that owls can exhibit a remarkable head stability during angular movement of the body about any axis passing through the skull. The vestibular apparatus in the owl is larger than in man, and a prominent crista neglecta is present. The tectorial membrane, the cupula, and the otolithic membranes of the utricle, saccule, and lagena are all attached to surfaces in addition to the surfaces hearing hair cells. These attachments are very substantial in the utricular otolithic membrane and in the cupula.

  4. The vestibular system of the owl

    NASA Technical Reports Server (NTRS)

    Money, K. E.; Correia, M. J.

    1973-01-01

    Five owls were given vestibular examinations, and two of them were sacrificed to provide serial histological sections of the temporal bones. The owls exhibited a curious variability in the postrotatory head nystagmus following abrupt deceleration; sometimes a brisk nystagnus with direction opposite to that appropriate to the stimulus would occur promptly after deceleration. It was found also that owls can exhibit a remarkable head stability during angular movement of the body about any axis passing through the skull. The vestibular apparatus in the owl is larger than in man, and a prominent crista neglecta is present. The tectorial membrane, the cupula, and the otolithic membranes of the utricle, saccule, and lagena are all attached to surfaces in addition to the surfaces hearing hair cells. These attachments are very substantial in the utricular otolithic membrane and in the cupula.

  5. Great horned owls are released at CCAFS

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Susan Small, director of the Florida Wildlife Hospital, holds a great horned owl before releasing it at Cape Canaveral Air Force Station, Complex 25/29. The owl is one of two found in June on the floor of CCAFS Hangar G, where their nest was located. They were treated at a local veterinary hospital and then taken to the Florida Wildlife Hospital in Melbourne for care and rehabilitation before release.

  6. Great horned owls are released at CCAFS

    NASA Technical Reports Server (NTRS)

    2000-01-01

    A great horned owl flies to freedom after its release at Cape Canaveral Air Force Station, Complex 25/29. The owl is one of two found in June on the floor of CCAFS Hangar G, where their nest was located. They were treated at a local veterinary hospital and then taken to the Florida Wildlife Hospital in Melbourne for care and rehabilitation before release.

  7. Great horned owls are released at CCAFS

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Eileen Olejarski (left), manager of Florida Wildlife Hospital, holds a great horned owl before releasing it at Cape Canaveral Air Force Station, Complex 25/29. The owl is one of two found in June on the floor of CCAFS Hangar G, where their nest was located. They were treated at a local veterinary hospital and then taken to the Florida Wildlife Hospital in Melbourne for care and rehabilitation before release.

  8. Great horned owls are released at CCAFS

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Eileen Olejarski (left), manager of Florida Wildlife Hospital, and Susan Small, director of the hospital, get ready to release two great horned owls at Cape Canaveral Air Force Station, Complex 25/29. The owls were found in June on the floor of CCAFS Hangar G, where their nest was located. They were treated at a local veterinary hospital and then taken to the Florida Wildlife Hospital in Melbourne for care and rehabilitation before release.

  9. Great horned owls are released at CCAFS

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Eileen Olejarski (left), manager of Florida Wildlife Hospital, and Susan Small, director of the hospital, remove two great horned owls from the vehicle before releasing them at Cape Canaveral Air Force Station, Complex 25/29. The owls were found in June on the floor of CCAFS Hangar G, where their nest was located. They were treated at a local veterinary hospital and then taken to the Florida Wildlife Hospital in Melbourne for care and rehabilitation before release..

  10. Great horned owls are released at CCAFS

    NASA Technical Reports Server (NTRS)

    2000-01-01

    A great horned owl flies to freedom after its release at Cape Canaveral Air Force Station, Complex 25/29. The owl is one of two found in June on the floor of CCAFS Hangar G, where their nest was located. They were treated at a local veterinary hospital and then taken to the Florida Wildlife Hospital in Melbourne for care and rehabilitation before release.

  11. Great horned owls are released at CCAFS

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Eileen Olejarski (left), manager of Florida Wildlife Hospital, and Susan Small, director of the hospital, get ready to release two great horned owls at Cape Canaveral Air Force Station, Complex 25/29. The owls were found in June on the floor of CCAFS Hangar G, where their nest was located. They were treated at a local veterinary hospital and then taken to the Florida Wildlife Hospital in Melbourne for care and rehabilitation before release.

  12. Great horned owls are released at CCAFS

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Eileen Olejarski (left), manager of Florida Wildlife Hospital, and Susan Small, director of the hospital, remove two great horned owls from the vehicle before releasing them at Cape Canaveral Air Force Station, Complex 25/29. The owls were found in June on the floor of CCAFS Hangar G, where their nest was located. They were treated at a local veterinary hospital and then taken to the Florida Wildlife Hospital in Melbourne for care and rehabilitation before release..

  13. Great horned owls are released at CCAFS

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Eileen Olejarski (left), manager of Florida Wildlife Hospital, holds a great horned owl before releasing it at Cape Canaveral Air Force Station, Complex 25/29. The owl is one of two found in June on the floor of CCAFS Hangar G, where their nest was located. They were treated at a local veterinary hospital and then taken to the Florida Wildlife Hospital in Melbourne for care and rehabilitation before release.

  14. Great horned owls are released at CCAFS

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Susan Small, director of the Florida Wildlife Hospital, holds a great horned owl before releasing it at Cape Canaveral Air Force Station, Complex 25/29. The owl is one of two found in June on the floor of CCAFS Hangar G, where their nest was located. They were treated at a local veterinary hospital and then taken to the Florida Wildlife Hospital in Melbourne for care and rehabilitation before release.

  15. Hypertrophic cardiomyopathy in owl monkeys (Aotus spp.).

    PubMed

    Knowlen, Grant G; Weller, Richard E; Perry, Ruby L; Baer, Janet F; Gozalo, Alfonso S

    2013-06-01

    Cardiac hypertrophy is a common postmortem finding in owl monkeys. In most cases the animals do not exhibit clinical signs until the disease is advanced, making antemortem diagnosis of subclinical disease difficult and treatment unrewarding. We obtained echocardiograms, electrocardiograms, and thoracic radiographs from members of a colony of owl monkeys that previously was identified as showing a 40% incidence of gross myocardial hypertrophy at necropsy, to assess the usefulness of these modalities for antemortem diagnosis. No single modality was sufficiently sensitive and specific to detect all monkeys with cardiac hypertrophy. Electrocardiography was the least sensitive method for detecting owl monkeys with hypertrophic cardiomyopathy. Thoracic radiographs were more sensitive than was electrocardiography in this context but cannot detect animals with concentric hypertrophy without an enlarged cardiac silhouette. Echocardiography was the most sensitive method for identifying cardiac hypertrophy in owl monkeys. The most useful parameters suggestive of left ventricular hypertrophy in our owl monkeys were an increased average left ventricular wall thickness to chamber radius ratio and an increased calculated left ventricular myocardial mass. Parameters suggestive of dilative cardiomyopathy were an increased average left ventricular myocardial mass and a decreased average ratio of left ventricular free wall thickness to left ventricular chamber radius. When all 4 noninvasive diagnostic modalities (physical examination, echocardiography, electrocardiography, and thoracic radiography) were used concurrently, the probability of detecting hypertrophic cardiomyopathy in owl monkeys was increased greatly.

  16. Hypertrophic Cardiomyopathy in Owl Monkeys (Aotus spp.)

    PubMed Central

    Knowlen, Grant G; Weller, Richard E; Perry, Ruby L; Baer, Janet F; Gozalo, Alfonso S

    2013-01-01

    Cardiac hypertrophy is a common postmortem finding in owl monkeys. In most cases the animals do not exhibit clinical signs until the disease is advanced, making antemortem diagnosis of subclinical disease difficult and treatment unrewarding. We obtained echocardiograms, electrocardiograms, and thoracic radiographs from members of a colony of owl monkeys that previously was identified as showing a 40% incidence of gross myocardial hypertrophy at necropsy, to assess the usefulness of these modalities for antemortem diagnosis. No single modality was sufficiently sensitive and specific to detect all monkeys with cardiac hypertrophy. Electrocardiography was the least sensitive method for detecting owl monkeys with hypertrophic cardiomyopathy. Thoracic radiographs were more sensitive than was electrocardiography in this context but cannot detect animals with concentric hypertrophy without an enlarged cardiac silhouette. Echocardiography was the most sensitive method for identifying cardiac hypertrophy in owl monkeys. The most useful parameters suggestive of left ventricular hypertrophy in our owl monkeys were an increased average left ventricular wall thickness to chamber radius ratio and an increased calculated left ventricular myocardial mass. Parameters suggestive of dilative cardiomyopathy were an increased average left ventricular myocardial mass and a decreased average ratio of left ventricular free wall thickness to left ventricular chamber radius. When all 4 noninvasive diagnostic modalities (physical examination, echocardiography, electrocardiography, and thoracic radiography) were used concurrently, the probability of detecting hypertrophic cardiomyopathy in owl monkeys was increased greatly. PMID:23759531

  17. Owls and larks in mice.

    PubMed

    Pfeffer, Martina; Wicht, Helmut; von Gall, Charlotte; Korf, Horst-Werner

    2015-01-01

    Humans come in different chronotypes and, particularly, the late chronotype (the so-called owl) has been shown to be associated with several health risks. A number of studies show that laboratory mice also display various chronotypes. In mice as well as in humans, the chronotype shows correlations with the period length and rhythm stability. In addition, some mouse models for human diseases show alterations in their chronotypic behavior, which are comparable to those humans. Thus, analysis of the behavior of mice is a powerful tool to unravel the molecular and genetic background of the chronotype and the prevalence of risks and diseases that are associated with it. In this review, we summarize the correlation of chronotype with free-running period length and rhythm stability in inbred mouse strains, in mice with a compromised molecular clockwork, and in a mouse model for neurodegeneration.

  18. Owl: Next Generation System Monitoring

    SciTech Connect

    Schulz, M; White, B S; McKee, S A; Lee, H S; Jeitner, J

    2005-02-16

    As microarchitectural and system complexity grows, comprehending system behavior becomes increasingly difficult, and often requires obtaining and sifting through voluminous event traces or coordinating results from multiple, non-localized sources. Owl is a proposed framework that overcomes limitations faced by traditional performance counters and monitoring facilities in dealing with such complexity by pervasively deploying programmable monitoring elements throughout a system. The design exploits reconfigurable or programmable logic to realize hardware monitors located at event sources, such as memory buses. These monitors run and writeback results autonomously with respect to the CPU, mitigating the system impact of interrupt-driven monitoring or the need to communicate irrelevant events to higher levels of the system. The monitors are designed to snoop any kind of system transaction, e.g., within the core, on a bus, across the wire, or within I/O devices.

  19. Owl Nest behind TV Building

    NASA Image and Video Library

    2014-03-18

    CAPE CANAVERAL, Fla. – At NASA's Kennedy Space Center in Florida, an Owl occupies a nest originally build by an Osprey atop a loudspeaker utility pole. Kennedy Space Center shares a boundary with the Merritt Island National Wildlife Refuge. The Refuge encompasses 140,000 acres that are a habitat for more than 331 species of birds, 31 mammals, 117 fishes, and 65 amphibians and reptiles. The marshes and open water of the refuge provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds, as well as a variety of insects. For more information, visit: http://www.nasa.gov/centers/kennedy/shuttleoperations/alligators/kscovr.html Photo credit: NASA/Dimitri Gerondidakis

  20. Improving strategies to assess competitive effects of barred owls on northern spotted owls in the Pacific Northwest

    USGS Publications Warehouse

    Wiens, J. David; Weekes, Anne

    2011-01-01

    A scientific study has determined that survey methods designed for spotted owls do not always detect barred owls that are actually present in spotted owl habitat. The researchers suggest that strategies to address potential interactions between spotted owls and barred owls will require carefully designed surveys that account for response behaviors and imperfect detection of both species. Species-specific sampling methods, which are proposed, can be used by forest managers to determine the occurrence and distribution of barred owls with high confidence. This fact sheet provides highlights of the research (Wiens and others, 2011).

  1. Falcon Herpesvirus, the Etiologic Agent of Inclusion Body Disease of Falcons

    PubMed Central

    Maré, C. J.; Graham, D. L.

    1973-01-01

    A viral agent has been isolated from five fatal cases of naturally occurring inclusion body disease in three different falcon species, namely, the prairie falcon (Falco mexicanus), the red-headed falcon (F. chiquera), and the peregrine falcon (F. peregrinus). The virus has been shown to possess the physical, chemical, and biological properties of a herpesvirus and has been used to reproduce inclusion body disease in the prairie falcon, merlin (F. columbarius), and American kestrel (F. sparverius). A similar disease was also produced with this virus in the great horned owl (Bubo virginianus), screech owl (Otus asio), and ring-necked turtle dove (Streptopelia risoria). Serological comparison of the falcon herpesvirus with other known avian herpesviruses revealed that the virus is antigenically closely related to a pigeon herpesvirus and an owl herpesvirus while differing from the former in host range. No antigenic relationship to infectious laryngotracheitis virus, duck virus enteritis, or Marek's disease virus could be demonstrated. Images PMID:4352453

  2. Falcon Herpesvirus, the etiologic agent of inclusion body disease of falcons.

    PubMed

    Maré, C J; Graham, D L

    1973-07-01

    A viral agent has been isolated from five fatal cases of naturally occurring inclusion body disease in three different falcon species, namely, the prairie falcon (Falco mexicanus), the red-headed falcon (F. chiquera), and the peregrine falcon (F. peregrinus). The virus has been shown to possess the physical, chemical, and biological properties of a herpesvirus and has been used to reproduce inclusion body disease in the prairie falcon, merlin (F. columbarius), and American kestrel (F. sparverius). A similar disease was also produced with this virus in the great horned owl (Bubo virginianus), screech owl (Otus asio), and ring-necked turtle dove (Streptopelia risoria). Serological comparison of the falcon herpesvirus with other known avian herpesviruses revealed that the virus is antigenically closely related to a pigeon herpesvirus and an owl herpesvirus while differing from the former in host range. No antigenic relationship to infectious laryngotracheitis virus, duck virus enteritis, or Marek's disease virus could be demonstrated.

  3. 75 FR 20425 - Additional Designations, Foreign Narcotics Kingpin Designation Act

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-19

    ... Narcotics Kingpin Designation Act. The names of the two individuals are as follows: 1. NA TCHUTO, Jose Americo Bubo (a.k.a. NA TCHUTE, Jose Americo Bubo); DOB 12 Jun 1952; POB N'cala, Guinea-Bissau... (a.k.a. CAMARA, Ibrahima Papa); nationality ] Guinea-Bissau; Air Force Chief of Staff of Guinea...

  4. Comparative food niche analysis of Strix Owls in Belarus

    Treesearch

    Alexey K. Tishechkin

    1997-01-01

    Three Strix species breed sympatrically in Belarus. The Tawny Owl (Strix aluco) is one of two commonest owl species in the country, and is distributed throughout the whole territory. Its' range overlaps widely with two other species, the Ural Owl (S. uralensis) which is common in the forests of the northern part and the Great...

  5. Chapter 9. Review of technical knowledge: Boreal owls

    Treesearch

    Gregory D. Hayward

    1994-01-01

    The boreal owl (Aegolius funereus), known as Tengmalm's owl in Eurasia, occurs throughout the holarctic in boreal climatic zones. This medium-size owl (100-170 g) occupies boreal and subalpine forests in an almost continuous circumboreal distribution that extends from Scandinavia eastward across the northern forests of Siberia and from Alaska...

  6. Threats to the viability of California spotted owls

    Treesearch

    John J. Keane

    2017-01-01

    The California spotted owl (Strix occidentalis occidentalis) is a species of conservation concern owing to threats to its habitat and populations. Verner et al. (1992) first assessed the status of the California spotted owl "The California Spotted Owl: A technical Assessment of it’s current status" (CASPO) and identified four factors as either threats or...

  7. Mexican Spotted Owl Recovery Plan, First Revision (Strix occidentalis lucida)

    Treesearch

    Mexican Spotted Owl Recovery Team U.S. Fish and Wildlife Service

    2012-01-01

    In 1993 the U.S. Fish and Wildlife Service (FWS) listed the Mexican spotted owl (Strix occidentalis lucida; "owl") as threatened under the Endangered Species Act (ESA). Critical habitat for the Mexican spotted owl was designated in 2004, comprising approximately 3.5 million hectares (ha) (8.6 million acres [ac]) on Federal lands in Arizona, Colorado, New...

  8. Owl Pellet Analysis--A Useful Tool in Field Studies

    ERIC Educational Resources Information Center

    Medlin, G. C.

    1977-01-01

    Describes a technique by which the density and hunting habits of owls can be inferred from their pellets. Owl pellets--usually small, cylindrical packages of undigested bone, hair, etc.--are regurgitated by a roosting bird. A series of activities based on owl pellets are provided. (CP)

  9. Chapter 14. Review of technical knowledge: Great gray owls

    Treesearch

    James R. Duncan; Patricia H. Hayward

    1994-01-01

    The great gray owl (Strix nebulosa) is the longest, but not heaviest, of the northern forest owls. Distributed holarctically across the boreal forests of North America and Eurasia, the great gray owl extends its range southward into the contiguous states by inhabiting forests other than the boreal type. The subalpine and montane forests of the...

  10. Owl Pellet Analysis--A Useful Tool in Field Studies

    ERIC Educational Resources Information Center

    Medlin, G. C.

    1977-01-01

    Describes a technique by which the density and hunting habits of owls can be inferred from their pellets. Owl pellets--usually small, cylindrical packages of undigested bone, hair, etc.--are regurgitated by a roosting bird. A series of activities based on owl pellets are provided. (CP)

  11. Comparative physiology of sound localization in four species of owls.

    PubMed

    Volman, S F; Konishi, M

    1990-01-01

    Bilateral ear asymmetry is found in some, but not all, species of owls. We investigated the neural basis of sound localization in symmetrical and asymmetrical species, to deduce how ear asymmetry might have evolved from the ancestral condition, by comparing the response properties of neurons in the external nucleus of the inferior colliculus (ICx) of the symmetrical burrowing owl and asymmetrical long-eared owl with previous findings in the symmetrical great horned owl and asymmetrical barn owl. In the ICx of all of these owls, the neurons had spatially restricted receptive fields, and auditory space was topographically mapped. In the symmetrical owls, ICx units were not restricted in elevation, and only azimuth was mapped in ICx. In the barn owl, the space map is two-dimensional, with elevation forming the second dimension. Receptive fields in the long-eared owl were somewhat restricted in elevation, but their tuning was not sharp enough to determine if elevation is mapped. In every species, the primary cue for azimuth was interaural time difference, although ICx units were also tuned for interaural intensity difference (IID). In the barn owl, the IIDs of sounds with frequencies between about 5 and 8 kHz vary systematically with elevation, and the IID selectivity of ICx neurons primarily encodes elevation. In the symmetrical owls, whose ICx neurons do not respond to frequencies above about 5 kHz, IID appears to be a supplementary cue for azimuth. We hypothesize that ear asymmetry can be exploited by owls that have evolved the higher-frequency hearing necessary to generate elevation cues. Thus, the IID selectivity of ICx neurons in symmetrical owls may preadapt them for asymmetry; the neural circuitry that underlies IID selectivity is already present in symmetrical owls, but because IID is not absolutely required to encode azimuth it can come to encode elevation in asymmetrical owls.

  12. F-OWL: An Inference Engine for Semantic Web

    NASA Technical Reports Server (NTRS)

    Zou, Youyong; Finin, Tim; Chen, Harry

    2004-01-01

    Understanding and using the data and knowledge encoded in semantic web documents requires an inference engine. F-OWL is an inference engine for the semantic web language OWL language based on F-logic, an approach to defining frame-based systems in logic. F-OWL is implemented using XSB and Flora-2 and takes full advantage of their features. We describe how F-OWL computes ontology entailment and compare it with other description logic based approaches. We also describe TAGA, a trading agent environment that we have used as a test bed for F-OWL and to explore how multiagent systems can use semantic web concepts and technology.

  13. Measurement of fetal biparietal diameter in owl monkeys (Aotus nancymaae).

    PubMed

    Schuler, A Michele; Brady, Alan G; Tustin, George W; Parks, Virginia L; Morris, Chris G; Abee, Christian R

    2010-09-01

    Owl monkeys are New World primates frequently used in biomedical research. Despite the historical difficulty of breeding owl monkeys in captivity, several productive owl monkey breeding colonies exist currently. The animals in the colony we describe here are not timed-pregnant, and determination of gestational age is an important factor in prenatal care. Gestational age of human fetuses is often determined by using transabdominal measurements of fetal biparietal diameter. The purpose of this study was to correlate biparietal diameter measurements with gestational age in owl monkeys. We found that biparietal diameter can be used to accurately predict gestational age in owl monkeys.

  14. Standardizing Legal Content with OWL and RDF

    NASA Astrophysics Data System (ADS)

    Hondros, Constantine

    Wolters Kluwer is one of the largest legal publishers in the world. Its various publishing units use a multitude of different formats to mark up what is effectively similar content. We describe a common content architecture based on OWL, RDF and XHTML that is used to build a standard representation of legal content, allowing publishable assets to be integrated across the enterprise. This architecture is governed by an OWL ontology that models the (occasionally complex) behaviour of legal documents and acts as a domain model of common legal metadata. How do OWL and RDF scale up to real-world publishing? We describe practical issues in producing and validating RDF on an industrial scale; in performance management; in handling fragmented ontologies; and the challenge of using RDF in a performant XSLT pipeline.

  15. Population trajectory of burrowing owls (Athene cunicularia) in eastern Washington

    USGS Publications Warehouse

    Conway, C.J.; Pardieck, K.L.

    2006-01-01

    Anecdotal evidence suggests that burrowing owls have declined in Washington. The Washington Department of Fish and Wildlife is currently conducting a status review for burrowing owls which will help determine whether they should be listed as threatened or endangered in the state. To provide insights into the current status of burrowing owls (Athene cunicularia), we analyzed data from the North American Breeding Bird Survey using two analytical approaches to determine their current population trajectory in eastern Washington. We used a one-sample t-test to examine whether trend estimates across all BBS routes in Washington differed from zero. We also used a mixed model analysis to estimate the rate of decline in number of burrowing owls detected between 1968 and 2005. The slope in number of burrowing owls detected was negative for 12 of the 16 BBS routes in Washington that have detected burrowing owls. Numbers of breeding burrowing owls detected in eastern Washington declined at a rate of 1.5% annually. We suggest that all BBS routes that have detected burrowing owls in past years in eastern Washington be surveyed annually and additional surveys conducted to track population trends of burrowing owls at finer spatial scales in eastern Washington. In the meantime, land management and regulatory agencies should ensure that publicly managed areas with breeding burrowing owls are not degraded and should implement education and outreach programs to promote protection of privately owned areas with breeding owls.

  16. Modeling interactions betweenspotted owl and barred owl populations in fire-prone forests

    EPA Science Inventory

    Background / Question / Methods Efforts to conserve northern spotted owls (Strix occidentalis caurina) in the eastern Cascades of Washington must merge the challenges of providing sufficient structurally complex forest habitat in a fire-prone landscape with the limitations impos...

  17. Modeling interactions betweenspotted owl and barred owl populations in fire-prone forests

    EPA Science Inventory

    Background / Question / Methods Efforts to conserve northern spotted owls (Strix occidentalis caurina) in the eastern Cascades of Washington must merge the challenges of providing sufficient structurally complex forest habitat in a fire-prone landscape with the limitations impos...

  18. Activity patterns of nesting Mexican Spotted Owls

    Treesearch

    David K. Delaney; Teryl G. Grubb; Paul Beier

    1999-01-01

    We collected 2,665 hr of behavioral information using video surveillance on 19 Mexican Spotted Owl (Strix occidentalis lucida) pairs between 25 April and 26 July 1996. Prey deliveries per day increased as the nesting season progressed, with an average of 2.68 prey deliveries during incubation, 4.10 items during brooding, and 4.51 items during the...

  19. Sherry Red Owl, Stands at Dawn Woman

    ERIC Educational Resources Information Center

    Crazy Bull, Cheryl

    2014-01-01

    This article introduces Sherry Red Owl, also known as "Stands at Dawn Woman," because she greets each day as a new opportunity and has spent her life working at new things. She worked at Sinte Gleska University (SGU) during its founding years, taught at an elementary school when few Native teachers were employed in the school systems,…

  20. Kenojuak Ashevak: "Young Owl Takes a Ride."

    ERIC Educational Resources Information Center

    Schwartz, Bernard

    1988-01-01

    Describes a lesson plan used to introduce K-3 students to a Canadian Inuit artist, to the personal and cultural context of the artwork, and to a simple printmaking technique. Includes background information on the artist, instructional strategies, and a print of the artist's "Young Owl Takes a Ride." (GEA)

  1. Sherry Red Owl, Stands at Dawn Woman

    ERIC Educational Resources Information Center

    Crazy Bull, Cheryl

    2014-01-01

    This article introduces Sherry Red Owl, also known as "Stands at Dawn Woman," because she greets each day as a new opportunity and has spent her life working at new things. She worked at Sinte Gleska University (SGU) during its founding years, taught at an elementary school when few Native teachers were employed in the school systems,…

  2. Kenojuak Ashevak: "Young Owl Takes a Ride."

    ERIC Educational Resources Information Center

    Schwartz, Bernard

    1988-01-01

    Describes a lesson plan used to introduce K-3 students to a Canadian Inuit artist, to the personal and cultural context of the artwork, and to a simple printmaking technique. Includes background information on the artist, instructional strategies, and a print of the artist's "Young Owl Takes a Ride." (GEA)

  3. Subtle Gardeners: Inland Predators Enrich Local Topsoils and Enhance Plant Growth

    PubMed Central

    Fedriani, José M.; Garrote, Pedro José; Delgado, María del Mar; Penteriani, Vincenzo

    2015-01-01

    Inland vertebrate predators could enrich of nutrients the local top soils in the area surrounding their nests and dens by depositing faeces, urine, and prey remains and, thus, alter the dynamics of plant populations. Surprisingly, and in contrast with convincing evidence from coastal habitats, whether and how this phenomenon occurs in inland habitats is largely uncertain even though these habitats represent a major fraction of the earth's surface. We investigated during two consecutive breeding seasons the potential enrichment of the top-soils associated with inland ground-nesting eagle owls Bubo bubo, as well as its possible consequences in the growth of two common annual grasses in southern Spain. Top-soils associated with owl nests differed strongly and significantly from control top-soils in chemical parameters, mainly fertility-related properties. Specifically, levels of available phosphorus, total nitrogen, organic matter, and available potassium were 49.1, 5.6, 3.1, and 2.7 times higher, respectively, in top-soils associated with owl nests as compared to control top-soils. Germination experiments in chambers indicated that nutrient enrichment by nesting owls enhanced seedling growth in both annual grasses (Phalaris canariensis and Avena sativa), with seedling size being 1.4–1.3 times higher in owl nest top-soils than in control top-soils. Our experimental study revealed that pervasive inland, predatory birds can profoundly enrich the topsoil around their nests and, thus, potentially enhance local vegetation growth. Because diverse inland vertebrate predators are widespread in most habitats they have a strong potential to enhance spatial heterogeneity, impinge on plant communities, and exert an overlooked effect on primary productivity worldwide. PMID:26383647

  4. Introgression and dispersal among spotted owl (Strix occidentalis) subspecies

    PubMed Central

    Funk, W Chris; Forsman, Eric D; Mullins, Thomas D; Haig, Susan M

    2008-01-01

    Abstract Population genetics plays an increasingly important role in the conservation and management of declining species, particularly for defining taxonomic units. Subspecies are recognized by several conservation organizations and countries and receive legal protection under the US Endangered Species Act (ESA). Two subspecies of spotted owls, northern (Strix occidentalis caurina) and Mexican (S. o. lucida) spotted owls, are ESA-listed as threatened, but the California (S. o. occidentalis) spotted owl is not listed. Thus, determining the boundaries of these subspecies is critical for effective enforcement of the ESA. We tested the validity of previously recognized spotted owl subspecies by analysing 394 spotted owls at 10 microsatellite loci. We also tested whether northern and California spotted owls hybridize as suggested by previous mitochondrial DNA studies. Our results supported current recognition of three subspecies. We also found bi-directional hybridization and dispersal between northern and California spotted owls centered in southern Oregon and northern California. Surprisingly, we also detected introgression of Mexican spotted owls into the range of northern spotted owls, primarily in the northern part of the subspecies’ range in Washington, indicating long-distance dispersal of Mexican spotted owls. We conclude with a discussion of the conservation implications of our study. PMID:25567499

  5. Introgression and dispersal among spotted owl (Strix occidentalis) subspecies.

    PubMed

    Funk, W Chris; Forsman, Eric D; Mullins, Thomas D; Haig, Susan M

    2008-02-01

    Population genetics plays an increasingly important role in the conservation and management of declining species, particularly for defining taxonomic units. Subspecies are recognized by several conservation organizations and countries and receive legal protection under the US Endangered Species Act (ESA). Two subspecies of spotted owls, northern (Strix occidentalis caurina) and Mexican (S. o. lucida) spotted owls, are ESA-listed as threatened, but the California (S. o. occidentalis) spotted owl is not listed. Thus, determining the boundaries of these subspecies is critical for effective enforcement of the ESA. We tested the validity of previously recognized spotted owl subspecies by analysing 394 spotted owls at 10 microsatellite loci. We also tested whether northern and California spotted owls hybridize as suggested by previous mitochondrial DNA studies. Our results supported current recognition of three subspecies. We also found bi-directional hybridization and dispersal between northern and California spotted owls centered in southern Oregon and northern California. Surprisingly, we also detected introgression of Mexican spotted owls into the range of northern spotted owls, primarily in the northern part of the subspecies' range in Washington, indicating long-distance dispersal of Mexican spotted owls. We conclude with a discussion of the conservation implications of our study.

  6. Comparison of Food Habits of the Northern Saw-whet Owl (Aegolius acadicus) and the Western Screech-owl (Otus kennicottii) in Southwestern Idaho

    Treesearch

    Charlotte Rains

    1997-01-01

    I compared the breeding-season diets of Northern Saw-whet Owls (Aegolius acadicus) and Western Screech-owls (Otus kennicottii). Prey items were obtained from regurgitated pellets collected from saw-whet owl and screech-owl nests found in nest boxes in the Snake River Birds of Prey National Conservation Area in southwestern Idaho....

  7. Causes of owl mortality in Hawaii, 1992-1994

    USGS Publications Warehouse

    Work, T.M.; Hale, J.

    1996-01-01

    Eighty-one barn owls (Tyto alba) and five Hawaiian owls or pueo (Asio flammeus sandwichensis) from Kauai, Oahu, Lanai, Molokai, Maui and Hawaii (USA) were evaluated for cause of death, November 1992 through August 1994. The most common cause of death in barn owls was trauma (50%) followed by infectious disease (28%) and emaciation (22%). Most traumas apparently resulted from vehicular collisions. Trichomoniasis was the predominant infectious disease and appeared to be a significant cause of death in barn owls in Hawaii. Pasteurellosis and aspergillosis were encountered less commonly. No predisposing cause of emaciation was detected. Stomach contents from 28 barn owls contained mainly insects (64%) of the family Tetigoniidae and Gryllidae, and rodents (18%); the remainder had mixtures of rodents and insects or grass. Three pueo died from trauma and one each died from emaciation and pasteurellosis. We found no evidence of organochlorine, organophosphorus, or carbamate pesticides as causes of death in pueo or barn owls.

  8. Causes of owl mortality in Hawaii, 1992-1994

    USGS Publications Warehouse

    Work, Thierry M.; Hale, Jon

    1996-01-01

    Eighty-one barn owls (Tyto alba) and five Hawaiian owls or pueo (Asio flammeus sandwichensis) from Kauai, Oahu, Lanai, Molokai, Maui and Hawaii (USA) were evaluated for cause of death, November 1992 through August 1994. The most common cause of death in barn owls was trauma (50%) followed by infectious disease (28%) and emaciation (22%). Most traumas apparently resulted from vehicular collisions. Trichomoniasis was the predominant infectious disease and appeared to be a significant cause of death in barn owls in Hawaii. Pasteurellosis and aspergillosis were encountered less commonly. No predisposing cause of emaciation was detected. Stomach contents from 28 barn owls contained mainly insects (64%) of the family Tetigoniidae and Gryllidae, and rodents (18%); the remainder had mixtures of rodents and insects or grass. Three pueo died from trauma and one each died from emaciation and pasteurellosis. We found no evidence of organochlorine, organophosphorus, or carbamate pesticides as causes of death in pueo or barn owls.

  9. Causes of owl mortality in Hawaii, 1992 to 1994.

    PubMed

    Work, T M; Hale, J

    1996-04-01

    Eighty-one barn owls (Tyto alba) and five Hawaiian owls or pueo (Asio flammeus sandwichensis) from Kauai, Oahu, Lanai, Molokai, Maui and Hawaii (USA) were evaluated for cause of death, November 1992 through August 1994. The most common cause of death in barn owls was trauma (50%) followed by infectious disease (28%) and emaciation (22%). Most traumas apparently resulted from vehicular collisions. Trichomoniasis was the predominant infectious disease and appeared to be a significant cause of death in barn owls in Hawaii. Pasteurellosis and aspergillosis were encountered less commonly. No predisposing cause of emaciation was detected. Stomach contents from 28 barn owls contained mainly insects (64%) of the family Tetigoniidae and Gryllidae, and rodents (18%); the remainder had mixtures of rodents and insects or grass. Three pueo died from trauma and one each died from emaciation and pasteurellosis. We found no evidence of organochlorine, organophosphorus, or carbamate pesticides as causes of death in pueo or barn owls.

  10. Cover of tall trees best predicts California spotted owl habitat

    Treesearch

    Malcolm P. North; Jonathan T. Kane; Van R. Kane; Gregory P. Asner; William Berigan; Derek J. Churchill; Scott Conway; R.J. Gutiérrez; Sean Jeronimo; John Keane; Alexander Koltunov; Tina Mark; Monika Moskal; Thomas Munton; Zachary Peery; Carlos Ramirez; Rahel Sollmann; Angela White; Sheila Whitmore

    2017-01-01

    Restoration of western dry forests in the USA often focuses on reducing fuel loads. In the range of the spotted owl, these treatments may reduce canopy cover and tree density, which could reduce preferred habitat conditions for the owl and other sensitive species. In particular, high canopy cover (≥70%) has been widely reported to be an important feature of spotted owl...

  11. Demography of Northern Spotted Owls in southwestern Oregon

    USGS Publications Warehouse

    Zabel, Cynthia J.; Salmons, Susan E.; Forsman, Eric D.; Destefano, Stephen; Raphael, Martin G.; Gutierrez, R.J.

    1996-01-01

    Northern Spotted Owls (Strix occidentalis caurina) are associated with lower elevation, commercially valuable, late-successional coniferous forests in the Pacific Northwest. Meta-analyses of demographic parameters indicate that Northern Spotted Owl populations are declining throughout their range (Anderson and Burnham 1992, Burnham et al. this volume). Recent research has attempted to determine whether management activities have affected the viability of Spotted Owl populations, and results have led to development of conservation plans for the species (Dawson et al. 1987, Thomas et al. 1990, Murphy and Noon 1992, USDI 1992, Thomas et al. 1993b).In the Recovery Plan for the Northern Spotted Owl (USDI 1992b) threats to the species were identified as small population sizes, declining populations, limited amounts of habitat, continued loss and fragmentation of habitat, geographically isolated populations, and predation and competition from other avian species. Weather and fire are natural processes that also may affect reproductive success of Spotted Owls. Weather may be a factor in the high annual variability in fecundity of Spotted Owls, as has been suggested for other predatory bird species (Newton, 1979, 1986). However, these factors have not been addressed in previous studies of Spotted Owls.Our objectives were to estimate survival, fecundity, and annual rates of population change (l) for resident, territorial female Spotted Owls at two study areas in the coastal mountains of southwestern Oregon. We tested if the amount of rainfall was correlated with reproduction of Spotted Owls. While surveying for Spotted Owls, we documented the increased presence of Barred Owls (Strix varia), a potential competitor of Spotted Owls.

  12. Potential trophic cascades triggered by the barred owl range expansion

    USGS Publications Warehouse

    Holm, Samantha R.; Noon, Barry R.; Wiens, David; Ripple, William J.

    2016-01-01

    Recently, the barred owl (Strix varia) has expanded its range into the Pacific Northwest of the United States resulting in pronounced effects on the demography and behavior of the northern spotted owl (S. occidentalis caurina). The range expansion has brought together historically allopatric species, creating the potential for significant changes in the avian predator community with possible cascading effects on food-web dynamics. The adverse effects of the barred owl on the behavior and demography of the northern spotted owl are well-documented, but little is known about the immediate and long-term effects changes in the predator community may have on native species composition and ecosystem processes. Based on northern spotted owl and barred owl selection for diet and habitat resources, there is a potential for trophic cascades within the region's predator and prey communities, differing responses by their shared and unique prey species, and possible direct and indirect effects on ecosystem processes. We explored the possible ecological consequences of the barred owl range expansion to wildlife communities of the Pacific Northwest based on the theoretical underpinnings of predator–prey relationships, interspecific competition, intraguild predation, and potential cascading trophic interactions. Negative effects on fitness of northern spotted owls because of interspecific competition with barred owls are strong selection forces that may contribute to the regional extinction of the northern spotted owl. In addition, we posit that shared prey species and those uniquely consumed by barred owls, along with other competing native predators, may experience changes in behavior, abundance, and distribution as a result of increased rates of predation by rapidly expanding populations of barred owls.

  13. A technique for evisceration as an alternative to enucleation in birds of prey: 19 cases.

    PubMed

    Murray, Maureen; Pizzirani, Stefano; Tseng, Florina

    2013-06-01

    Ocular trauma is common in birds of prey presented to wildlife clinics and rehabilitation centers. Enucleation is the procedure most commonly described for treatment of end-stage ocular disease or chronically painful eyes in birds; however, there are several disadvantages and risks to this procedure. While evisceration has been suggested as an alternative, it has not been described for multiple cases or with long-term follow-up data in birds of prey. This report details an evisceration technique performed in 5 captive birds of prey of 4 different species (1 eastern screech owl [Megascops asio], 1 great horned owl [Bubo virginianus], 2 red-tailed hawks [Buteo jamaicensis], and 1 bald eagle [Haliaeetus leucocephalus]) with long-term follow-up information. In addition, this report describes 14 cases of free-living owls of 3 different species (1 great horned owl, 4 barred owls [Strix varia], and 9 eastern screech owls) on which this technique was performed from 2004 to 2011 and which were subsequently released to the wild. Because of the limited risk of complications and the less-severe disruption of facial symmetry, which may be particularly important in owls that are candidates for release to the wild, evisceration should be considered over enucleation in birds of prey that require surgical intervention for the management of severe sequelae to ocular trauma.

  14. Translating the Foundational Model of Anatomy into OWL

    PubMed Central

    Noy, Natalya F.; Rubin, Daniel L.

    2008-01-01

    The Foundational Model of Anatomy (FMA) represents the result of manual and disciplined modeling of the structural organization of the human body. It is a tremendous resource in bioinformatics that facilitates sharing of information among applications that use anatomy knowledge. The FMA was developed in Protégé and the Protégé frames language is the canonical representation language for the FMA. We present a translation of the original Protégé frame representation of the FMA into OWL. Our effort is complementary to the earlier efforts to represent FMA in OWL and is focused on two main goals: (1) representing only the information that is explicitly present in the frames representation of the FMA or that can be directly inferred from the semantics of Protégé frames; (2) representing all the information that is present in the frames representation of the FMA, thus producing an OWL representation for the complete FMA. Our complete representation of the FMA in OWL consists of two components: an OWL DL component that contains the FMA constructs that are compatible with OWL DL; and an OWL Full component that imports the OWL DL component and adds the FMA constructs that OWL DL does not allow. PMID:18688289

  15. Translating the Foundational Model of Anatomy into OWL.

    PubMed

    Noy, Natalya F; Rubin, Daniel L

    2008-01-01

    The Foundational Model of Anatomy (FMA) represents the result of manual and disciplined modeling of the structural organization of the human body. It is a tremendous resource in bioinformatics that facilitates sharing of information among applications that use anatomy knowledge. The FMA was developed in Protégé and the Protégé frames language is the canonical representation language for the FMA. We present a translation of the original Protégé frame representation of the FMA into OWL. Our effort is complementary to the earlier efforts to represent FMA in OWL and is focused on two main goals: (1) representing only the information that is explicitly present in the frames representation of the FMA or that can be directly inferred from the semantics of Protégé frames; (2) representing all the information that is present in the frames representation of the FMA, thus producing an OWL representation for the complete FMA. Our complete representation of the FMA in OWL consists of two components: an OWL DL component that contains the FMA constructs that are compatible with OWL DL; and an OWL Full component that imports the OWL DL component and adds the FMA constructs that OWL DL does not allow.

  16. Detecting Burrowing Owl Bloodmeals in Pulex irritans (Siphonaptera: Pulicidae).

    PubMed

    Graham, Christine B; Eisen, Rebecca J; Belthoff, James R

    2016-03-01

    Pulex irritans L. is a cosmopolitan flea species that infests a wide variety of hosts. In North America it generally parasitizes large wild mammals, but in the Pacific Northwest an association has emerged between P. irritans and the western burrowing owl (Athene cunicularia hypugaea). While investigators have recognized this association for decades, it has not been clear if P. irritans feeds on burrowing owls, or if the owls serve exclusively as phoretic hosts. Here we describe using a real-time assay that was originally developed to identify bloodmeals in Ugandan cat fleas (Ctenocephalides felis Bouché) to detect burrowing owl DNA in P. irritans collected from burrowing owls in southern Idaho. Of 50 fleas tested, 12 had no detectable vertebrate bloodmeal. The remaining 38 (76%) contained burrowing owl DNA. The assay did not detect vertebrate DNA in unfed fleas exposed to owl or mouse pelts and is therefore unlikely to detect DNA in fleas from vertebrates that have served exclusively as phoretic hosts. We conclude that P. irritans feeds on burrowing owls. We discuss the potential implications of this finding for burrowing owl conservation and enzootic plague dynamics. Published by Oxford University Press on behalf of Entomological Society of America 2015. This work is written by US Government employees and is in the public domain in the US.

  17. Detecting Burrowing Owl Bloodmeals in Pulex irritans (Siphonaptera: Pulicidae)

    PubMed Central

    Graham, Christine B.; Eisen, Rebecca J.; Belthoff, James R.

    2017-01-01

    Pulex irritansL. is a cosmopolitan flea species that infests a wide variety of hosts. In North America it generally parasitizes large wild mammals, but in the Pacific Northwest an association has emerged between P. irritans and the western burrowing owl (Athene cunicularia hypugaea). While investigators have recognized this association for decades, it has not been clear if P. irritans feeds on burrowing owls, or if the owls serve exclusively as phoretic hosts. Here we describe using a real-time assay that was originally developed to identify bloodmeals in Ugandan cat fleas (Ctenocephalides felis Bouché) to detect burrowing owl DNA in P. irritans collected from burrowing owls in southern Idaho. Of 50 fleas tested, 12 had no detectable vertebrate bloodmeal. The remaining 38 (76%) contained burrowing owl DNA. The assay did not detect vertebrate DNA in unfed fleas exposed to owl or mouse pelts and is therefore unlikely to detect DNA in fleas from vertebrates that have served exclusively as phoretic hosts. We conclude that P. irritans feeds on burrowing owls. We discuss the potential implications of this finding for burrowing owl conservation and enzootic plague dynamics. PMID:26545716

  18. Live trapping of hawks and owls

    USGS Publications Warehouse

    Stewart, R.E.; Cope, J.B.; Robbins, C.S.

    1945-01-01

    1. Hawks of six species (80 individuals) and owls of five species (37 individuals) were trapped for banding from November 1, 1943, to. May 26,1944. 2. In general, pole traps proved better than hand-operated traps or automatic traps using live bait. 3. Verbail pole traps proved very efficient, and were much more humane than padded steel traps because they rarely injured a captured bird. 4: Unbaited Verbail traps took a variety of raptors, in rough proportion to their local abundance, although slightly more of beneficial species were caught than of harmful types. 5. Hawks and owls were retrapped more readily in Verbail traps than in other types tried. 6. The number of song birds caught in Verbail traps was negligible. 7. Crows and vultures were not taken in Verbail traps, but possibly could be caught with bait.

  19. Habitat Suitability Index Models: Spotted owl

    USGS Publications Warehouse

    Laymon, Stephen A.; Salwasser, Hal; Barrett, Reginald H.

    1985-01-01

    A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the spotted owl (Strix occidentalis). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  20. Genetic identification of spotted owls, barred owls, and their hybrids: Legal implications of hybrid identity

    USGS Publications Warehouse

    Haig, Susan M.; Wennerberg, Liv; Mullins, Thomas D.; Forsman, E.D.; Trail, P.

    2004-01-01

    Recent population expansion of Barred Owls ( Strix varia) into western North America has led to concern that they may compete with and further harm the Northern Spotted Owl ( S. occidentalis caurina), which is already listed as threatened under the U.S. Endangered Species Act (ESA). Because they hybridize, there is a legal need under the ESA for forensic identification of both species and their hybrids. We used mitochondrial control-region DNA and amplified fragment-length polymorphism (AFLP) analyses to assess maternal and biparental gene flow in this hybridization process. Mitochondrial DNA sequences (524 base pairs) indicated large divergence between Barred and Spotted Owls (13.9%). Further, the species formed two distinct clades with no signs of previous introgression. Fourteen diagnostic AFLP bands also indicated extensive divergence between the species, including markers differentiating them. Principal coordinate analyses and assignment tests clearly supported this differentiation. We found that hybrids had unique genetic combinations, including AFLP markers from both parental species, and identified known hybrids as well as potential hybrids with unclear taxonomic status. Our analyses corroborated the findings of extensive field studies that most hybrids genetically sampled resulted from crosses between female Barred Owls and male Spotted Owls. These genetic markers make it possible to clearly identify these species as well as hybrids and can now be used for research, conservation, and law enforcement. Several legal avenues may facilitate future conservation of Spotted Owls and other ESA-listed species that hybridize, including the ESA similarity-of-appearance clause (section 4[e]) and the Migratory Bird Treaty Act. The Migratory Bird Treaty Act appears to be the most useful route at this time.

  1. Geographical assemblages of European raptors and owls

    NASA Astrophysics Data System (ADS)

    López-López, Pascual; Benavent-Corai, José; García-Ripollés, Clara

    2008-09-01

    In this work we look for geographical structure patterns in European raptors (Order: Falconiformes) and owls (Order: Strigiformes). For this purpose we have conducted our research using freely available tools such as statistical software and databases. To perform the study, presence-absence data for the European raptors and owl species (Class Aves) were downloaded from the BirdLife International website. Using the freely available "pvclust" R-package, we applied similarity Jaccard index and cluster analysis in order to delineate biogeographical relationships for European countries. According to the cluster of similarity, we found that Europe is structured into two main geographical assemblages. The larger length branch separated two main groups: one containing Iceland, Greenland and the countries of central, northern and northwestern Europe, and the other group including the countries of eastern, southern and southwestern Europe. Both groups are divided into two main subgroups. According to our results, the European raptors and owls could be considered structured into four meta-communities well delimited by suture zones defined by Remington (1968) [Remington, C.L., 1968. Suture-zones of hybrid interaction between recently joined biotas. Evol. Biol. 2, 321-428]. Climatic oscillations during the Quaternary Ice Ages could explain at least in part the modern geographical distribution of the group.

  2. Calling behavior of spotted owls in Northern Arizona

    Treesearch

    Jospeh L. Ganey

    1990-01-01

    I studied the calling behavior of radio-tagged Mexican Spotted Owls (Strix occidentalis lucida) in northern Arizona. Owls used a variety of calls, with three call types (Four-note Location Call, Contact Call, and Bark Series) accounting for 86% of calling bouts heard. These calls were used by both sexes, but in significantly different proportions....

  3. Owl broadcast surveys in the Foothills Model Forest, Alberta, Canada

    Treesearch

    D. Lisa Takats; Geoffrey L. Holroyd

    1997-01-01

    Broadcast surveys are used to determine the presence and relative abundance of nocturnal owls, but there has been little effort to standardize such surveys. This paper examines broadcast survey data collected in 1995 and 1996 in the Foothills Model Forest, Alberta, Canada. Three hundred calls from six species of owls were recorded at 893 stops for a call rate of 0.34...

  4. Burrowing owl foods in Conata Basin, South Dakota

    Treesearch

    James C. MacCracken; Daniel W. Uresk; Richard M. Hansen

    1985-01-01

    Burrowing Owls (Athene cunicularia) were studied in a prairie dog town of southwestern South Dakota. Pellets regurgitated by Burrowing Owls contained a wide variety of prey remains. Insects, spiders, small mammals, and vegetation were the most frequent items identified in the pellets. Mammals were consumed most frequently during spring and early...

  5. Food habits of Mexican Spotted Owls in Arizona

    Treesearch

    Joseph L. Ganey

    1992-01-01

    The Spotted Owl (Strix occidentalis) is most common in mature and old-growth coniferous forests throughout much of its range (Forsman et al. 1984, Laymon 1988, Ganey and Balda 1989a, Thomas et al. 1990). Proximate factors underlying habitat selection in Spotted Owls are understood poorly. Abundance and availability of food, however, may be a key...

  6. Winter prey caching by northern hawk owls in Minnesota

    Treesearch

    Richard R. Schaefer; D. Craig Rudolph; Jesse F. Fagan

    2007-01-01

    Northern Hawk Owls (Surnia ulula) have been reported to cache prey during the breeding season for later consumption, but detailed reports of prey caching during the non-breeding season are comparatively rare. We provided prey to four individual Northern Hawk Owls in wintering areas in northeastern Minnesota during 2001 and 2005 and observed their...

  7. Population dynamics of Lanyu Scops Owls (Otus elegans botelensis)

    Treesearch

    L. L. Severinghaus

    1997-01-01

    Monthly visits to Lanyu Island have been made to study Lanyu Scops Owls (Otus elegans botelensis) since 1986. This population has been surveyed by regular census and playback counts, by color banding, by monitoring the survival, reproduction and movements of individual owls, and by mapping and documenting the change in nest trees.

  8. Habitat selection by Mexican Spotted Owls in Northern Arizona

    Treesearch

    Joseph L. Ganey; Russell P. Balda

    1994-01-01

    We compared use of seven habitat types to availability of those types within the home ranges of eight radio-tagged Mexican Spotted Owls (Strix occidentalis lucida). When all habitat types were considered simultaneously, habitat use differed from habitat availability for each owl. Patterns of habitat use varied among individuals and with respect to...

  9. Nesting habitat of Mexican spotted owls in the Sacramento Mountains

    Treesearch

    Joseph L. Ganey; Darrell L. Apprill; Todd A. Rawlinson; Sean C. Kyle; Ryan S. Jonnes; James P. Ward

    2013-01-01

    Understanding the habitat relationships of rare species is critical to conserving populations and habitats of those species. Nesting habitat is suspected to limit distribution of the threatened Mexican spotted owl (Strix occidentalis lucida), and may vary among geographic regions. We studied selection of nesting habitat by Mexican spotted owls within their home ranges...

  10. Report on the Western Burrowing Owl (Speotyto cunicularia) conservation workshop

    Treesearch

    Geoffrey L. Holroyd; Troy I. Wellicome

    1997-01-01

    This workshop was convened to review the current status of the Western Burrowing Owl (Speotyto cunicularia hypugaea) in North America, to discuss means by which we can improve our knowledge of this owl, and to initiate conservation action to benefit the species.

  11. Associations between forest fire and Mexican spotted owls

    Treesearch

    Jeffrey S. Jenness; Paul Beier; Joseph L. Ganey

    2004-01-01

    In 1993, the US Fish and Wildlife Service listed the Mexican spotted owl (Strix occidentalis lucida) as threatened, in part because of the rising threat to its habitat from stand-replacing wildfires. In 1997, we surveyed 33 owl sites that, in the previous four years, had burned at various levels ranging from light controlled burns to stand-replacing fires. We compared...

  12. Survival and reproduction of radio-marked adult spotted owls.

    Treesearch

    C.C. Foster; E.D. Forsman; E.C. Meslow; G.S. Miller; J.A. Reid; F.F. Wagner; A.B. Carey; J.B. Lint

    1992-01-01

    We compared survival, reproduction, and body mass of radio-marked and non radio-marked spotted owls (Strix occidentalis) to determine if backpack radios influenced reproduction or survival. In most study areas and years, there were no differences (P > 0.05) in survival of males and females or in survival of radio-marked versus banded owls. There...

  13. Forest stand structure of the northern spotted owl's foraging habitat.

    Treesearch

    Malcolm P. North; Jerry F. Franklin; Andrew B. Carey; Eric D. Forsman; Tom. Hamer

    1999-01-01

    Although the spotted owl's close association with old growth has been extensively studied, it more difficult to identify and quantify the abundance of particular stand structures associated with preferred owl foraging sites. Old-growth forests have a suite of characteristics that distinguish them from younger forests but which also make it difficult to isolate...

  14. Northern spotted owls: influence of prey base and landscape character.

    Treesearch

    A.B. Carey; S.P. Horton; B.L. Biswell

    1992-01-01

    We studied prey populations and the use and composition of home ranges of 47 Northern Spotted Owls (Strix occidentalis caurina) over 12 mo in five landscapes in two forest types in southwestern Oregon. We measured 1-yr home ranges of 23 owl pairs, 2-yr home ranges of 13 pairs, and 3-yr home ranges of 3 pairs. The landscapes differed in the degree...

  15. Thermal regimes of Mexican spotted owl nest stands

    Treesearch

    Joseph L. Ganey

    2004-01-01

    To evaluate the hypothesis that spotted owls (Strix occidentalis) select habitats with cool microclimates to avoid high daytime temperatures, I sampled thermal regimes in nest areas used by Mexican spotted owls (S. o. lucida) in northern Arizona. I sampled air temperature at 30-min intervals in 30 pairs of nest and random sites...

  16. Hunting increases adaptive auditory map plasticity in adult barn owls.

    PubMed

    Bergan, Joseph F; Ro, Peter; Ro, Daniel; Knudsen, Eric I

    2005-10-19

    The optic tectum (OT) of barn owls contains topographic maps of auditory and visual space. Barn owls reared with horizontally displacing prismatic spectacles (prisms) acquire a novel auditory space map in the OT that restores alignment with the prismatically displaced visual map. Although juvenile owls readily acquire alternative maps of auditory space as a result of experience, this plasticity is reduced greatly in adults. We tested whether hunting live prey, a natural and critically important behavior for barn owls, increases auditory map plasticity in adult owls. Two groups of naive adult owls were fit with prisms. The first group was fed dead mice during 10 weeks of prism experience, while the second group was required to hunt live prey for an identical period of time. When the owls hunted live prey, auditory maps shifted substantially farther (five times farther, on average) and the consistency of tuning curve shifts within each map increased. Only a short period of time in each day, during which the two groups experienced different conditions, accounts for this effect. In addition, increased map plasticity correlated with behavioral improvements in the owls' ability to strike and capture prey. These results indicate that the experience of hunting dramatically increases adult adaptive plasticity in this pathway.

  17. An Overview of OWL, a Language for Knowledge Representation.

    ERIC Educational Resources Information Center

    Szolovits, Peter; And Others

    This is a description of the motivation and overall organization of the OWL language for knowledge representation. OWL consists of a linguistic memory system (LMS), a memory of concepts in terms of which all English phrases and all knowledge of an application domain are represented; a theory of English grammar which tells how to map English…

  18. Brood division and postnesting behavior of Flammulated Owls

    Treesearch

    Brian D. Linkhart; Richard T. Reynolds

    1987-01-01

    The Flammulated Owl (Otus flammeolus) is widely distributed in the montane forests of western North America (Bent 1938). The owl is insectivorous (Ross 1969) and is presumed to be migratory in the northern part of its range (Balda et al. 1975). Little is known of the nesting behavior of this species, especially during the postfledging period. Here,...

  19. Population distribution and trends of California spotted owls

    Treesearch

    Douglas J. Tempel; R.J. Gutiérrez; M. Zachariah Peery

    2017-01-01

    Following Verner et al.’s (1992) technical assessment of the California spotted owl (CASPO), we divided the range of the California spotted owl (Strix occidentalis occidentalis) into two major physiographic provinces: the Sierra Nevada and the mountains of southern California (Tehachapi Pass was the demarcation between the regions). Verner et al. (...

  20. Mathematical demography of spotted owls in the Pacific Northwest

    Treesearch

    B.R. Noon; C.M. Biles

    1990-01-01

    We examined the mathematical demography of northern spotted owls (Strix occidentalis caurina) using simple deterministic population models. Our goals were to gain insights into the life history strategy, to determine demographic attributes most affecting changes in population size, and to provide guidelines for effective management of spotted owl...

  1. Hypopi (Acari:Hypoderatidae) from owls (Aves:Strigiformes:Strigidae).

    PubMed

    Pence, D B; Bergan, J F

    1996-09-01

    Hypopi (deutonymphs) of the family Hypoderatidae were found in a barn owl, Tyto alba (Scopoli), and a burrowing owl, Speotyto cunicularia (Molina), from Texas. A redescription is provided for mature specimens of the hypopus of Tytodectes (Tytodectes) tyto Fain from the subcutaneous adipose tissues of the pelvic region in the barn owl. The hypopus of Tytodectes (Tytodectes) speotyto n. sp. is described from specimens in the subcutaneous adipose tissues of the pelvic region and in the adipose tissues of the intermuscular fasciae of the ankle in the burrowing owl. T. (T.) speotyto appears most similar in size and chaetotaxy to T. (T.) glaucidii Cerný described from the Cuban pygmy owl, Glaucidium siju (d'Orbigny), in Cuba, but differs in the presence of a spine on tibia IV, which also occurs in T. (T.) tyto. Both of the former species have the anterior apodemes of coxae I fused in a simple V and lack a sternum. They differ from T. (T.) tyto which has the anterior apodemes of coxae I fused in a Y and there is a well developed sternum. Based on the above 3 described hypopi, the hypoderatids of owls represent an assemblage of small closely related, but easily differentiated, species. The occurrence of a few specimens of Neottialges evansi Fain in the barn owl and Hypodectes (Hypodectoides) propus (Nitzsch) in the burrowing owl probably represent examples of host capture by hypopi that normally occur in cormorants and pigeons, herons or egrets, respectively.

  2. The hunting behavior of eastern screech-owls (Otus asio)

    Treesearch

    Carlo M. Abbruzzese; Gary Ritchison

    1997-01-01

    We studied the nocturnal hunting behavior of eight radio-tagged Eastern Screech-owls (Otus asio; five females and three males) during the period from November 1994 through March 1995. Screech-owls selected low perches when hunting (x = 1.66 m), presumably to obtain a clear view of the ground and an unobstructed flight path to prey. Low perches may...

  3. Spotted owls: resource and space use in mosaic landscapes.

    Treesearch

    A.B. Carey; K.C. Peeler

    1995-01-01

    Home ranges of 14 pairs of spotted owls (Strix occidentalis) were studied over four to six seasons in three southwest Oregon landscapes that differed in prey base and degree of forest fragmentation. The general theory of space use and the biology of spotted owls was used to construct a scheme for spatiotemporal analyses that provided insights...

  4. Protozoal hepatitis in a western burrowing owl (Athene cunicularia hypugaea)

    USGS Publications Warehouse

    Franson, J. Christian

    2017-01-01

    A western burrowing owl (Athene cunicularia hypugaea) found dead in southern California had many light-colored lesions visible grossly on its liver, and histopathology revealed extensive necrosis throughout the hepatic parenchyma. Single-celled organisms were seen in clear spaces within the areas of necrosis. The owl was diagnosed with protozoal hepatitis.

  5. Methods and materials, for locating and studying spotted owls.

    Treesearch

    Eric D. Forsman

    1983-01-01

    Nocturnal calling surveys are the most effective and most frequently used technique for locating spotted owls. Roosts and general nest locations may be located during the day by calling in suspected roost or nest areas. Specific nest trees are located by: (1) baiting with a live mouse to induce owls to visit the nest, (2) calling in suspected nest areas to stimulate...

  6. An evolving process: protecting spotted owl habitat through landscape management

    Treesearch

    Michael Feinstein; John Lehmkuhl; Paul Hessburg

    2010-01-01

    A network of late-successional forest reserves is central to the Northwest Forest Plan, the guiding vision for managing federal forests in Washington, Oregon, and northern California within the range of the northern spotted owl. These reserves were created to maintain older forest structure as habitat for the northern spotted owl, marbled murrelet, and other associated...

  7. Flammulated Owls (Otus flammeolus) breeding in deciduous forests

    Treesearch

    Carl D. Marti

    1997-01-01

    The first studies of nesting Flammulated Owls (Otus flammeolus) established the idea that the species needs ponderosa pine (Pinus ponderosa) forests for breeding. In northern Utah, Flammulated Owls nested in montane deciduous forests dominated by quaking aspen (Populus tremuloides). No pines were present but...

  8. Wing loading in 15 species of North American owls

    Treesearch

    David H. Johnson

    1997-01-01

    Information on wing morphology is important in understanding the mechanics and energetics of flight and in aspects related to reversed sexual size dimorphism in owls. I summarized wing span, wing area, wing loading, root box, and aspect ratio calculations from the available literature and from 113 owls examined in this study. Wing loading estimates for 15 species...

  9. Long-eared owls nesting in Badlands National Park

    Treesearch

    Deborah D. Paulson; Carolyn Hull Sieg

    1985-01-01

    Long-eared Owls nest at high densities locally over the Great Plains where suitable habitat is limited (Bent 1938), yet , according to Whitney et al. (1978), this species is rare to uncommon in South Dakota. Especially west of the Missouri River, few nesting records have been reported. This paper reports the occurrence of Long-eared Owls in the Badlands National Park...

  10. Predator facilitation or interference: a game of vipers and owls.

    PubMed

    Embar, Keren; Raveh, Ashael; Hoffmann, Ishai; Kotler, Burt P

    2014-04-01

    In predator-prey foraging games, the prey's reaction to one type of predator may either facilitate or hinder the success of another predator. We ask, do different predator species affect each other's patch selection? If the predators facilitate each other, they should prefer to hunt in the same patch; if they interfere, they should prefer to hunt alone. We performed an experiment in a large outdoor vivarium where we presented barn owls (Tyto alba) with a choice of hunting greater Egyptian gerbils (Gerbillus pyramidum) in patches with or without Saharan horned vipers (Cerastes cerastes). Gerbils foraged on feeding trays set under bushes or in the open. We monitored owl location, activity, and hunting attempts, viper activity and ambush site location, and the foraging behavior of the gerbils in bush and open microhabitats. Owls directed more attacks towards patches with vipers, and vipers were more active in the presence of owls. Owls and vipers facilitated each other's hunting through their combined effect on gerbil behavior, especially on full moon nights when vipers are more active. Owls forced gerbils into the bushes where vipers preferred to ambush, while viper presence chased gerbils into the open where they were exposed to owls. Owls and vipers took advantage of their indirect positive effect on each other. In the foraging game context, they improve each other's patch quality and hunting success.

  11. Is the northern Saw-whet Owl (Aegolius acadicus) nomadic?

    Treesearch

    Jeffery S. Marks

    1997-01-01

    The first recorded nesting of a Northern Saw-whet Owl (Aegolius acadicus) in the Snake River Birds of Prey Area in southwestern Idaho occurred in a nest box in 1986. Occupancy of nest boxes by Northern Saw-whet Owls varied considerably (0 to 8 nests per year) over the next 10 years. Numbers of rodents fluctuated during this same period, and the...

  12. Habitat fragmentation and the Burrowing Owls (Speotyto cunicularia) in Saskatchewan

    Treesearch

    Robert G. Warnock; Paul C. James

    1997-01-01

    The relationship between landscape (125,664 ha circular plots) fragmentation patterns and the spatial distribution of Burrowing Owls (Speotyto cunicularia) was investigated in the heavily fragmented grasslands of Saskatchewan. Data were collected from 152 Burrowing Owl sites and 250 random sites located on 1990 LANDSAT-TM satellite images and 1:250,...

  13. Forest structure within barred owl (Strix varia) home ranges in the eastern cascade range, Washington

    Treesearch

    Peter H. Singleton

    2015-01-01

    Competitive interactions with Barred Owls (Strix varia) are an important factor contributing to the decline of the Northern Spotted Owl (Strix occidentalis caurina) population. Understanding the degree of similarity in fine-scale habitat associations for Spotted Owls and Barred Owls will help land managers evaluate whether...

  14. Using tape playback of the staccato song to document Boreal Owl (Aegolius funereus) reproduction

    Treesearch

    Dale W. Stahlecker

    1997-01-01

    Tape playback of the staccato song of the Boreal Owl (Aegolius funereus richardsoni) proved useful in attracting fledglings of both North American Aegolius species. No Boreal Owl nests were found in 8 hours of daytime searches. However, six Boreal Owls, including three to four fledglings at two locations, one Northern Saw-whet Owl (A....

  15. The effects of habitat, climate, and Barred Owls on long-term demography of Northern Spotted Owls

    USGS Publications Warehouse

    Dugger, Catherine; Forsman, Eric D.; Franklin, Alan B.; Davis, Raymond J.; White, Gary C.; Schwarz, Carl J.; Burnham, Kenneth P.; Nichols, James D.; Hines, James E.; Yackulic, Charles B.; Doherty, Paul F.; Bailey, Larissa; Clark, Darren A.; Ackers, Steven H.; Andrews, Lawrence S.; Augustine, Benjamin; Biswell, Brian L.; Blakesley, Jennifer; Carlson, Peter C.; Clement, Matthew J.; Diller, Lowell V.; Glenn, Elizabeth M.; Green, Adam; Gremel, Scott A.; Herter, Dale R.; Higley, J. Mark; Hobson, Jeremy; Horn, Rob B.; Huyvaert, Kathryn P.; McCafferty, Christopher; McDonald, Trent; McDonnell, Kevin; Olson, Gail S.; Reid, Janice A.; Rockweit, Jeremy; Ruiz, Viviana; Saenz, Jessica; Sovern, Stan G.

    2016-01-01

    Estimates of species' vital rates and an understanding of the factors affecting those parameters over time and space can provide crucial information for management and conservation. We used mark–recapture, reproductive output, and territory occupancy data collected during 1985–2013 to evaluate population processes of Northern Spotted Owls (Strix occidentalis caurina) in 11 study areas in Washington, Oregon, and northern California, USA. We estimated apparent survival, fecundity, recruitment, rate of population change, and local extinction and colonization rates, and investigated relationships between these parameters and the amount of suitable habitat, local and regional variation in meteorological conditions, and competition with Barred Owls (Strix varia). Data were analyzed for each area separately and in a meta-analysis of all areas combined, following a strict protocol for data collection, preparation, and analysis. We used mixed effects linear models for analyses of fecundity, Cormack-Jolly-Seber open population models for analyses of apparent annual survival (ϕ), and a reparameterization of the Jolly-Seber capture–recapture model (i.e. reverse Jolly-Seber; RJS) to estimate annual rates of population change (λRJS) and recruitment. We also modeled territory occupancy dynamics of Northern Spotted Owls and Barred Owls in each study area using 2-species occupancy models. Estimated mean annual rates of population change (λ) suggested that Spotted Owl populations declined from 1.2% to 8.4% per year depending on the study area. The weighted mean estimate of λ for all study areas was 0.962 (± 0.019 SE; 95% CI: 0.925–0.999), indicating an estimated range-wide decline of 3.8% per year from 1985 to 2013. Variation in recruitment rates across the range of the Spotted Owl was best explained by an interaction between total winter precipitation and mean minimum winter temperature. Thus, recruitment rates were highest when both total precipitation (29 cm) and

  16. Chemical composition of uropygial gland secretions of owls.

    PubMed

    Jacob, J; Poltz, J

    1974-05-01

    The compositions of the uropygial gland secretions of the long-eared owl, eagle owl, and barn owl have been determined. The waxes of the first two owls, which are closely related, are composed of 2-alkyl-substituted fatty acids and n- or monomethyl-branched alcohols with even-numbered branching positions. In addition, some dimethyl-substituted alkanols were observed. In contrast to these waxes, the secretion of the barn owl is composed of 3-methyl- and 3,5-, 3,7-, 3,9-, 3,11-, 3,13-, and 3,15-dimethyl-branched fatty acids and n- as well as monomethyl-substituted alkanols branched at positions 2, 3, and 4. The mass spectra of esters of 2-alkyl-substituted fatty acids are discussed.

  17. Spotted owls and old growth logging in the pacific northwest.

    PubMed

    Doak, D

    1989-12-01

    Northern Spotted Owls, Strix occidentalis caurina, require large tracts of old-growth conifer forest to survive and reproduce. Much of this forest has been or is being cut by commercial logging operations, with uncertain consequences for the owls. In this paper I present simulation models of owl population change over the next 100 years, as summing a variety of scenarios for habitat destruction and fragmentation. My analysis differs from previous models by incorporating patchy territory distribution and random environmental fluctuations. Fragmented and patchy habitat distributions are common problems for endangered organisms, but they have received little attention from modelers. My results indicate that yearly fluctuations in breeding success have little impact on owl populations, but that spatial structure is quite important and should be considered in planning forest preservation. The simulations suggest that for all reasonable parameter values the proposed US. Forest Service logging plans will lead to the demise of the owls.

  18. Easy Extraction of Terms and Definitions with OWL2TL.

    PubMed

    Judkins, John; Utecht, Joseph; Brochhausen, Mathias

    2016-08-01

    Facilitating good communication between semantic web specialists and domain experts is necessary to efficient ontology development. This development may be hindered by the fact that domain experts tend to be unfamiliar with tools used to create and edit OWL files. This is true in particular when changes to definitions need to be reviewed as often as multiple times a day. We developed "OWL to Term List" (OWL2TL) with the goal of allowing domain experts to view the terms and definitions of an OWL file organized in a list that is updated each time the OWL file is updated. The tool is available online and currently generates a list of terms, along with additional annotation properties that are chosen by the user, in a format that allows easy copying into a spreadsheet.

  19. Easy Extraction of Terms and Definitions with OWL2TL

    PubMed Central

    Judkins, John; Utecht, Joseph; Brochhausen, Mathias

    2016-01-01

    Facilitating good communication between semantic web specialists and domain experts is necessary to efficient ontology development. This development may be hindered by the fact that domain experts tend to be unfamiliar with tools used to create and edit OWL files. This is true in particular when changes to definitions need to be reviewed as often as multiple times a day. We developed "OWL to Term List" (OWL2TL) with the goal of allowing domain experts to view the terms and definitions of an OWL file organized in a list that is updated each time the OWL file is updated. The tool is available online and currently generates a list of terms, along with additional annotation properties that are chosen by the user, in a format that allows easy copying into a spreadsheet. PMID:28035214

  20. Increase in distribution records of owl species in Manitoba based on a volunteer nocturnal survey using Boreal Owl (Aegolius funereus) and Great Gray Owl (Strix nebulosa) playback

    Treesearch

    James R. Duncan; Patricia A. Duncan

    1997-01-01

    From 1991 through 1995, extensive owl surveys were conducted in late March and early April in Manitoba. Prior to these surveys, distribution records of owls covered only 16-71 per cent of their expected range in Manitoba. The degree to which the survey increased the documented range varied from no increase (6 of 12 species) up to an 88 per cent increase for the...

  1. Propagation of barn owls in captivity

    USGS Publications Warehouse

    Maestrelli, J.R.

    1973-01-01

    Some aspects of the biology and life history of native birds often are more readily obtained in captivity than in the field. This is particularly true in evaluating the effects of pesticides or other pollutants on birds, because establishing cause-and-effect relationships requires experimental studies. Few wild species have been bred in captivity with sufficient success to permit the large-scale studies that are needed. This paper reports successful efforts to breed Barn Owls (Tyto alba prolinicola) in captivity and presents biological data concerning reproduction.

  2. Mapping between the OBO and OWL ontology languages

    PubMed Central

    2011-01-01

    Background Ontologies are commonly used in biomedicine to organize concepts to describe domains such as anatomies, environments, experiment, taxonomies etc. NCBO BioPortal currently hosts about 180 different biomedical ontologies. These ontologies have been mainly expressed in either the Open Biomedical Ontology (OBO) format or the Web Ontology Language (OWL). OBO emerged from the Gene Ontology, and supports most of the biomedical ontology content. In comparison, OWL is a Semantic Web language, and is supported by the World Wide Web consortium together with integral query languages, rule languages and distributed infrastructure for information interchange. These features are highly desirable for the OBO content as well. A convenient method for leveraging these features for OBO ontologies is by transforming OBO ontologies to OWL. Results We have developed a methodology for translating OBO ontologies to OWL using the organization of the Semantic Web itself to guide the work. The approach reveals that the constructs of OBO can be grouped together to form a similar layer cake. Thus we were able to decompose the problem into two parts. Most OBO constructs have easy and obvious equivalence to a construct in OWL. A small subset of OBO constructs requires deeper consideration. We have defined transformations for all constructs in an effort to foster a standard common mapping between OBO and OWL. Our mapping produces OWL-DL, a Description Logics based subset of OWL with desirable computational properties for efficiency and correctness. Our Java implementation of the mapping is part of the official Gene Ontology project source. Conclusions Our transformation system provides a lossless roundtrip mapping for OBO ontologies, i.e. an OBO ontology may be translated to OWL and back without loss of knowledge. In addition, it provides a roadmap for bridging the gap between the two ontology languages in order to enable the use of ontology content in a language independent manner

  3. Mapping between the OBO and OWL ontology languages.

    PubMed

    Tirmizi, Syed Hamid; Aitken, Stuart; Moreira, Dilvan A; Mungall, Chris; Sequeda, Juan; Shah, Nigam H; Miranker, Daniel P

    2011-03-07

    Ontologies are commonly used in biomedicine to organize concepts to describe domains such as anatomies, environments, experiment, taxonomies etc. NCBO BioPortal currently hosts about 180 different biomedical ontologies. These ontologies have been mainly expressed in either the Open Biomedical Ontology (OBO) format or the Web Ontology Language (OWL). OBO emerged from the Gene Ontology, and supports most of the biomedical ontology content. In comparison, OWL is a Semantic Web language, and is supported by the World Wide Web consortium together with integral query languages, rule languages and distributed infrastructure for information interchange. These features are highly desirable for the OBO content as well. A convenient method for leveraging these features for OBO ontologies is by transforming OBO ontologies to OWL. We have developed a methodology for translating OBO ontologies to OWL using the organization of the Semantic Web itself to guide the work. The approach reveals that the constructs of OBO can be grouped together to form a similar layer cake. Thus we were able to decompose the problem into two parts. Most OBO constructs have easy and obvious equivalence to a construct in OWL. A small subset of OBO constructs requires deeper consideration. We have defined transformations for all constructs in an effort to foster a standard common mapping between OBO and OWL. Our mapping produces OWL-DL, a Description Logics based subset of OWL with desirable computational properties for efficiency and correctness. Our Java implementation of the mapping is part of the official Gene Ontology project source. Our transformation system provides a lossless roundtrip mapping for OBO ontologies, i.e. an OBO ontology may be translated to OWL and back without loss of knowledge. In addition, it provides a roadmap for bridging the gap between the two ontology languages in order to enable the use of ontology content in a language independent manner.

  4. Geographic variation and genetic structure in Spotted Owls

    USGS Publications Warehouse

    Haig, Susan M.; Wagner, R.S.; Forsman, E.D.; Mullins, Thomas D.

    2001-01-01

    We examined genetic variation, population structure, and definition of conservation units in Spotted Owls (Strix occidentalis). Spotted Owls are mostly non-migratory, long-lived, socially monogamous birds that have decreased population viability due to their occupation of highly-fragmented late successional forests in western North America. To investigate potential effects of habitat fragmentation on population structure, we used random amplified polymorphic DNA (RAPD) to examine genetic variation hierarchically among local breeding areas, subregional groups, regional groups, and subspecies via sampling of 21 breeding areas (276 individuals) among the three subspecies of Spotted Owls. Data from 11 variable bands suggest a significant relationship between geographic distance among local breeding groups and genetic distance (Mantel r = 0.53, P < 0.02) although multi-dimensional scaling of three significant axes did not identify significant grouping at any hierarchical level. Similarly, neighbor-joining clustering of Manhattan distances indicated geographic structure at all levels and identified Mexican Spotted Owls as a distinct clade. RAPD analyses did not clearly differentiate Northern Spotted Owls from California Spotted Owls. Among Northern Spotted Owls, estimates of population differentiation (FST) ranged from 0.27 among breeding areas to 0.11 among regions. Concordantly, within-group agreement values estimated via multi-response permutation procedures of Jaccarda??s distances ranged from 0.22 among local sites to 0.11 among regions. Pairwise comparisons of FST and geographic distance within regions suggested only the Klamath region was in equilibrium with respect to gene flow and genetic drift. Merging nuclear data with recent mitochondrial data provides support for designation of an Evolutionary Significant Unit for Mexican Spotted Owls and two overlapping Management Units for Northern and California Spotted Owls.

  5. First detection of Borrelia burgdorferi-antibodies in free-living birds of prey from Eastern Westphalia, Germany.

    PubMed

    Büker, M; Picozzi, K; Kolb, S; Hatt, J-M

    2013-07-01

    Borrelia (B.) burgdorferi sensu lato, the causative agent of Lyme disease, is the most important arthropod-borne zoonosis-pathogen in the Northern hemisphere. Besides small mammals, birds, primarily Passeriformes and sea birds, play an important role in the transmission, distribution and maintenance of this disease. Previous studies on birds have focused mainly on the detection of Borrelia-infected ticks. However, the presence or absence of an infected tick cannot be taken as an indicator of the infective status of the avian host; to date this area of research has not been explored. In this study, serological analyses of blood collected from free-living birds of prey (n = 29) at the rehabilitation centre in Eastern Westphalia, Germany, highlights that birds of prey are also susceptible to B. burgdorferi and react immunologically to an infection. Increased antibody-levels could be found by using a modified Indirect Immunofluorescent-testing in two common buzzards, Buteo buteo, and two eagle owls, Bubo bubo. Further research regarding the serological diagnostics of B. burgdorferi within the avian host is required. In the future, it should be taken into account that birds of prey can be reservoirs for B. burgdorferi, as well as carriers of infected ticks; although at present their epidemiological importance is still to be confirmed.

  6. Population Characteristics May Reduce the Levels of Individual Call Identity

    PubMed Central

    Delgado, María del Mar; Caferri, Eleonora; Méndez, Maria; Godoy, José A.; Campioni, Letizia; Penteriani, Vincenzo

    2013-01-01

    Individual variability influences the demographic and evolutionary dynamics of spatially structured populations, and conversely ecological and evolutionary dynamics provide the context under which variations at the individual level occur. Therefore, it is essential to identify and characterize the importance of the different factors that may promote or hinder individual variability. Animal signaling is a prime example of a type of behavior that is largely dependent on both the features of individuals and the characteristics of the population to which they belong. After 10 years studying the dynamics of a population of a long-lived species, the eagle owl (Bubo bubo), we investigated the emergence and maintenance of traits that reveal individual identity by focusing on vocal features. We found that individuals inhabiting a high density population characterized by a relative lack of heterogeneity (in terms of prey availability and breeding success) among breeding sites might be selected for reducing the levels of identity. Two non-mutually exclusive hypotheses may explain the structural call patterns we detected: (1) similarity in calls may be principally a consequence of the particular characteristics of the population; and (2) high density may encourage individuals to mimic each other’s vocalizations in a cascade effect, leading to a widespread and unique communication network. PMID:24204869

  7. How the owl resolves auditory coding ambiguity

    PubMed Central

    Mazer, James A.

    1998-01-01

    The barn owl (Tyto alba) uses interaural time difference (ITD) cues to localize sounds in the horizontal plane. Low-order binaural auditory neurons with sharp frequency tuning act as narrow-band coincidence detectors; such neurons respond equally well to sounds with a particular ITD and its phase equivalents and are said to be phase ambiguous. Higher-order neurons with broad frequency tuning are unambiguously selective for single ITDs in response to broad-band sounds and show little or no response to phase equivalents. Selectivity for single ITDs is thought to arise from the convergence of parallel, narrow-band frequency channels that originate in the cochlea. ITD tuning to variable bandwidth stimuli was measured in higher-order neurons of the owl’s inferior colliculus to examine the rules that govern the relationship between frequency channel convergence and the resolution of phase ambiguity. Ambiguity decreased as stimulus bandwidth increased, reaching a minimum at 2–3 kHz. Two independent mechanisms appear to contribute to the elimination of ambiguity: one suppressive and one facilitative. The integration of information carried by parallel, distributed processing channels is a common theme of sensory processing that spans both modality and species boundaries. The principles underlying the resolution of phase ambiguity and frequency channel convergence in the owl may have implications for other sensory systems, such as electrolocation in electric fish and the computation of binocular disparity in the avian and mammalian visual systems. PMID:9724807

  8. How the owl tracks its prey – II

    PubMed Central

    Takahashi, Terry T.

    2010-01-01

    Barn owls can capture prey in pitch darkness or by diving into snow, while homing in on the sounds made by their prey. First, the neural mechanisms by which the barn owl localizes a single sound source in an otherwise quiet environment will be explained. The ideas developed for the single source case will then be expanded to environments in which there are multiple sound sources and echoes – environments that are challenging for humans with impaired hearing. Recent controversies regarding the mechanisms of sound localization will be discussed. Finally, the case in which both visual and auditory information are available to the owl will be considered. PMID:20889819

  9. Reproduction of the owl monkey (Aotus spp.) in captivity.

    PubMed

    Málaga, C A; Weller, R E; Buschbom, R L; Baer, J F; Kimsey, B B

    1997-06-01

    The reproduction performance of captive owl monkeys, a breed used extensively in biomedical research, was observed at the Battelle Primate Facility (BPF). The colony grew through captive breeding, imports from the Peruvian Primatological Project, and others to a peak size of 730. It included seven karyotypes of Aotus sp. Results showed that owl monkeys can breed successfully in a laboratory in numbers sufficient to sustain modest research programs. Reproductive success increases when pairs are compatible, of the same karyotype, and stabilized; however, mated pairs of different karyotype are also productive. Under conditions of controlled lighting and heating, owl monkeys at BPF showed no birth peak nor birth season.

  10. OWL 2 learn profile: an ontology sublanguage for the learning domain.

    PubMed

    Heiyanthuduwage, Sudath R; Schwitter, Rolf; Orgun, Mehmet A

    2016-01-01

    Many experimental ontologies have been developed for the learning domain for use at different institutions. These ontologies include different OWL/OWL 2 (Web Ontology Language) constructors. However, it is not clear which OWL 2 constructors are the most appropriate ones for designing ontologies for the learning domain. It is possible that the constructors used in these learning domain ontologies match one of the three standard OWL 2 profiles (sublanguages). To investigate whether this is the case, we have analysed a corpus of 14 ontologies designed for the learning domain. We have also compared the constructors used in these ontologies with those of the OWL 2 RL profile, one of the OWL 2 standard profiles. The results of our analysis suggest that the OWL 2 constructors used in these ontologies do not exactly match the standard OWL 2 RL profile, but form a subset of that profile which we call OWL 2 Learn.

  11. Modeling co-occurrence of northern spotted and barred owls: accounting for detection probability differences

    USGS Publications Warehouse

    Bailey, Larissa L.; Reid, Janice A.; Forsman, Eric D.; Nichols, James D.

    2009-01-01

    Barred owls (Strix varia) have recently expanded their range and now encompass the entire range of the northern spotted owl (Strix occidentalis caurina). This expansion has led to two important issues of concern for management of northern spotted owls: (1) possible competitive interactions between the two species that could contribute to population declines of northern spotted owls, and (2) possible changes in vocalization behavior and detection probabilities of northern spotted owls induced by presence of barred owls. We used a two-species occupancy model to investigate whether there was evidence of competitive exclusion between the two species at study locations in Oregon, USA. We simultaneously estimated detection probabilities for both species and determined if the presence of one species influenced the detection of the other species. Model selection results and associated parameter estimates provided no evidence that barred owls excluded spotted owls from territories. We found strong evidence that detection probabilities differed for the two species, with higher probabilities for northern spotted owls that are the object of current surveys. Non-detection of barred owls is very common in surveys for northern spotted owls, and detection of both owl species was negatively influenced by the presence of the congeneric species. Our results suggest that analyses directed at hypotheses of barred owl effects on demographic or occupancy vital rates of northern spotted owls need to deal adequately with imperfect and variable detection probabilities for both species.

  12. Multidrug-resistant Salmonella enterica Serovar Typhimurium Monophasic Variant 4,12:i:- Isolated from Asymptomatic Wildlife in a Catalonian Wildlife Rehabilitation Center, Spain.

    PubMed

    Molina-López, Rafael A; Vidal, Anna; Obón, Elena; Martín, Marga; Darwich, Laila

    2015-07-01

    Wildlife can act as long-term asymptomatic reservoirs for zoonotic bacteria, such as Salmonella. The prevalence and antimicrobial-susceptibility profiles of Salmonella spp. were assessed in 263 cases in wildlife from 22 animal orders from a wildlife rehabilitation center in Catalonia (NE Spain), September 2013-May 2014. Eleven of 263 tested animals were positive for Salmonella spp., representing an overall prevalence of 4.2%. Prevalences by taxonomic categories were 2% in mammals, 4.7% in birds, and 4.5% in reptiles. By species, one each of European hedgehog (Erinaceus europeus; from a sample of n = 26), Eurasian Eagle Owl (Bubo bubo; n = 2), Barn Owl (Tyto alba; n = 3), Tawny Owl (Strix aluco; n = 20), Egyptian Vulture (Neophron percnopterus; n = 1), Griffon Vulture (Gyps fulvus; n = 1), and Hoopoe (Upupa epops; n = 2), and two each Common Kestrels (Falco tinnunculus; n = 16) and pond sliders (Trachemys scripta; n = 25) were positive for Salmonella. By serotyping, seven of eleven isolates were classified as S. enterica subsp. enterica serovar Typhimurium, and five of seven belonged to the monophasic variant 4,12:i:-. All the monophasic variants were isolated from birds (4/5 in raptors) and showed a multidrug-resistance (MDR) profile to at least ampicillin, streptomycin, sulfonamide, and tetracycline (R-type ASSuT), and up to 12 antibiotics. The large proportion of S. Typhimurium monophasic MDR strains detected in wildlife never treated with antibiotics, especially in raptors, adds more complexity to the epidemiologic control of one of the most frequent serovars involved in human and livestock infection.

  13. Seropositivity and risk factors associated with Toxoplasma gondii infection in wild birds from Spain.

    PubMed

    Cabezón, Oscar; García-Bocanegra, Ignacio; Molina-López, Rafael; Marco, Ignasi; Blanco, Juan M; Höfle, Ursula; Margalida, Antoni; Bach-Raich, Esther; Darwich, Laila; Echeverría, Israel; Obón, Elena; Hernández, Mauro; Lavín, Santiago; Dubey, Jitender P; Almería, Sonia

    2011-01-01

    Toxoplasma gondii is a zoonotic intracellular protozoan parasite of worldwide distribution that infects many species of warm-blooded animals, including birds. To date, there is scant information about the seropositivity of T. gondii and the risk factors associated with T. gondii infection in wild bird populations. In the present study, T. gondii infection was evaluated on sera obtained from 1079 wild birds belonging to 56 species (including Falconiformes (n=610), Strigiformes (n=260), Ciconiiformes (n=156), Gruiformes (n=21), and other orders (n=32), from different areas of Spain. Antibodies to T. gondii (modified agglutination test, MAT titer ≥1:25) were found in 282 (26.1%, IC(95%:)23.5-28.7) of the 1079 birds. This study constitute the first extensive survey in wild birds species in Spain and reports for the first time T. gondii antibodies in the griffon vulture (Gyps fulvus), short-toed snake-eagle (Circaetus gallicus), Bonelli's eagle (Aquila fasciata), golden eagle (Aquila chrysaetos), bearded vulture (Gypaetus barbatus), osprey (Pandion haliaetus), Montagu's harrier (Circus pygargus), Western marsh-harrier (Circus aeruginosus), peregrine falcon (Falco peregrinus), long-eared owl (Asio otus), common scops owl (Otus scops), Eurasian spoonbill (Platalea leucorodia), white stork (Ciconia ciconia), grey heron (Ardea cinerea), common moorhen (Gallinula chloropus); in the International Union for Conservation of Nature (IUCN) "vulnerable" Spanish imperial eagle (Aquila adalberti), lesser kestrel (Falco naumanni) and great bustard (Otis tarda); and in the IUCN "near threatened" red kite (Milvus milvus). The highest seropositivity by species was observed in the Eurasian eagle owl (Bubo bubo) (68.1%, 98 of 144). The main risk factors associated with T. gondii seropositivity in wild birds were age and diet, with the highest exposure in older animals and in carnivorous wild birds. The results showed that T. gondii infection is widespread and can be at a high level in

  14. 29. November 1969 'OWL' CAPITAL BETWEEN WINDOWS ON SOUTH WALL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    29. November 1969 'OWL' CAPITAL BETWEEN WINDOWS ON SOUTH WALL OF RIGGS LIBRARY, SECOND LEVEL - Georgetown University, Healy Building, Thirty-seventh & O Streets, Northwest, Washington, District of Columbia, DC

  15. OWL: A Condor Based Workflow Management System for JWST

    NASA Astrophysics Data System (ADS)

    Pierfederici, F.; Swam, M.; Greene, G.; Kyprianou, M.; Gaffney, N.

    2012-09-01

    The Open Workflow Layer (OWL) is an open source Workflow Management System (WMS) developed at the Space Telescope Science Institute. OWL is being designed for the James Webb Space Telescope (JWST) science data processing using the Hubble Space Telescope (HST) as a test bed. It is however very general and could be applied to many other missions and data processing applications. OWL is a thin Python layer that provides advanced workflow management, GUIs and a data-centric view on top of Condor, a widely used open source batch scheduling system. As such, OWL can transparently take advantage of the many features offered by Condor without having to re-implement them from scratch.

  16. Ectoparasites of Burrowing Owls (Athene cunicularia hypugaea) wintering in southern Texas

    USGS Publications Warehouse

    Skoruppa, M.K.; Pearce, B.; Woodin, M.C.; Hickman, G.C.

    2006-01-01

    Fifteen Western Burrowing Owls (Athene cunicularia hypugaea) were captured over two winters (2001-2003) in southern Texas and examined for ectoparasites. Four of the 15 owls (27%) harbored feather lice, and the maximum number of lice found on any individual was ??? three. Two species of feather lice were found: Colpocephalum pectinatum occurred on three of the owls, and Strigiphilus speotyti was found on four owls. No fleas or other ectoparasites were found on any of the Burrowing Owls. The low diversity and numbers of ectoparasites suggest that ectoparasites are not threatening the health of wintering Burrowing Owls in southern Texas.

  17. Semantically-Rigorous Systems Engineering Modeling Using Sysml and OWL

    NASA Technical Reports Server (NTRS)

    Jenkins, J. Steven; Rouquette, Nicolas F.

    2012-01-01

    The Systems Modeling Language (SysML) has found wide acceptance as a standard graphical notation for the domain of systems engineering. SysML subsets and extends the Unified Modeling Language (UML) to define conventions for expressing structural, behavioral, and analytical elements, and relationships among them. SysML-enabled modeling tools are available from multiple providers, and have been used for diverse projects in military aerospace, scientific exploration, and civil engineering. The Web Ontology Language (OWL) has found wide acceptance as a standard notation for knowledge representation. OWL-enabled modeling tools are available from multiple providers, as well as auxiliary assets such as reasoners and application programming interface libraries, etc. OWL has been applied to diverse projects in a wide array of fields. While the emphasis in SysML is on notation, SysML inherits (from UML) a semantic foundation that provides for limited reasoning and analysis. UML's partial formalization (FUML), however, does not cover the full semantics of SysML, which is a substantial impediment to developing high confidence in the soundness of any conclusions drawn therefrom. OWL, by contrast, was developed from the beginning on formal logical principles, and consequently provides strong support for verification of consistency and satisfiability, extraction of entailments, conjunctive query answering, etc. This emphasis on formal logic is counterbalanced by the absence of any graphical notation conventions in the OWL standards. Consequently, OWL has had only limited adoption in systems engineering. The complementary strengths and weaknesses of SysML and OWL motivate an interest in combining them in such a way that we can benefit from the attractive graphical notation of SysML and the formal reasoning of OWL. This paper describes an approach to achieving that combination.

  18. Longevity records for male and female flammulated owls

    Treesearch

    Richard T. Reynolds; Brian D. Linkhart

    1990-01-01

    A female Flammulated Owl (Otus flammeolus), banded as a breeding adult on 14 Jul. 1981 in central Colorado, was last captured on 9 Jul. 1987. On the same study area, a male Flammulated Owl was banded as a nestling on 15 Jul. 1981 and was last recaptured at a nest 2.5 km distant from its natal site on 6 Jul. 1989. These establish the longevity for...

  19. Diets and foraging behavior of northern spotted owls in Oregon.

    Treesearch

    Eric D. Forsman; Robert G. Anthony; E. Charles Meslow; Cynthia J. Zabel

    2004-01-01

    We describe local, regional, and annual variation in diets of northern Spotted Owls (Strix occidaatalis caurina) in Oregon based on 24497 prey collected at 1118 owl territories in 1970-2003. The sample included 91.5% mammals, 4.3% birds, 4.1% insects, and 0.1% other prey. The diet included 2131 species, including 49 mammals, 41 birds, 3 reptiles, 1...

  20. An Evaluation of Knowledge Base Systems for Large OWL Datasets

    DTIC Science & Technology

    2004-01-01

    An Evaluation of Knowledge Base Systems for Large OWL Datasets Yuanbo Guo, Zhengxiang Pan, and Jeff Heflin Computer Science & Engineering ...present our work on evaluating knowledge base sys- tems with respect to use in large OWL applications. To this end, we have de- veloped the Lehigh...University Benchmark (LUBM). The benchmark is in- tended to evaluate knowledge base systems with respect to extensional queries over a large dataset that

  1. Semantically-Rigorous Systems Engineering Modeling Using Sysml and OWL

    NASA Technical Reports Server (NTRS)

    Jenkins, J. Steven; Rouquette, Nicolas F.

    2012-01-01

    The Systems Modeling Language (SysML) has found wide acceptance as a standard graphical notation for the domain of systems engineering. SysML subsets and extends the Unified Modeling Language (UML) to define conventions for expressing structural, behavioral, and analytical elements, and relationships among them. SysML-enabled modeling tools are available from multiple providers, and have been used for diverse projects in military aerospace, scientific exploration, and civil engineering. The Web Ontology Language (OWL) has found wide acceptance as a standard notation for knowledge representation. OWL-enabled modeling tools are available from multiple providers, as well as auxiliary assets such as reasoners and application programming interface libraries, etc. OWL has been applied to diverse projects in a wide array of fields. While the emphasis in SysML is on notation, SysML inherits (from UML) a semantic foundation that provides for limited reasoning and analysis. UML's partial formalization (FUML), however, does not cover the full semantics of SysML, which is a substantial impediment to developing high confidence in the soundness of any conclusions drawn therefrom. OWL, by contrast, was developed from the beginning on formal logical principles, and consequently provides strong support for verification of consistency and satisfiability, extraction of entailments, conjunctive query answering, etc. This emphasis on formal logic is counterbalanced by the absence of any graphical notation conventions in the OWL standards. Consequently, OWL has had only limited adoption in systems engineering. The complementary strengths and weaknesses of SysML and OWL motivate an interest in combining them in such a way that we can benefit from the attractive graphical notation of SysML and the formal reasoning of OWL. This paper describes an approach to achieving that combination.

  2. Ferruginous pygmy-owl (Glaucidium brasilianum) and eastern screech-owl (Megascopes asio): new hosts for Philornis mimicola (Diptera: Muscidae) and Ornithodoros concanensis (Acari: Argasidae).

    PubMed

    Proudfoot, Glenn A; Teel, Pete D; Mohr, Rachel M

    2006-10-01

    While banding ferruginous pygmy-owls (Glaucidium brasilianum) and Eastern screech-owls (Megascops asio) in south Texas during 2004, we recorded Philornis mimicola (Diptera: Muscidae) and Ornithodoros concanensis (Acari: Argasidae) parasitizing nestlings. Inspection of nestlings revealed 54 P. mimicola and one O. concanensis. Inspection of nest material revealed 111 P. mimicola, including 57 puparia. The effect (e.g., blood loss, anemia) of these hematophagous parasites might have contributed to the demise of at least one Eastern screech-owl nestling. This is the first record of P. mimicola and O. concanensis parasitizing ferruginous pygmy-owls and Eastern screech-owls.

  3. California spotted owls: Chapter 5 in Managing Sierra Nevada forests

    USGS Publications Warehouse

    Roberts, Suzanne C.; Brooks, Matthew L.

    2012-01-01

    California spotted owls (Strix occidentalis occidentalis) are habitat specialists that are strongly associated with late-successional forests. For nesting and roosting, they require large trees and snags embedded in a stand with a complex forest structure (Blakesley et al. 2005, Gutiérrez et al. 1992, Verner et al. 1992b). In mixedconifer forests of the Sierra Nevada, California spotted owls typically nest and roost in stands with high canopy closure (≥75 percent) [Note: when citing studies, we use terminology consistent with Jennings et al. (1999), however, not all studies properly distinguish between canopy cover and closure and often use the terms interchangeably (see chapter 14 for clarification)] and an abundance of large trees (>24 in (60 cm) diameter at breast height [d.b.h.]) (Bias and Gutiérrez 1992, Gutiérrez et al. 1992, LaHaye et al. 1997, Moen and Gutiérrez 1997, Verner et al. 1992a). The California spotted owl guidelines (Verner et al. 1992b) effectively summarized much of the information about nesting and roosting habitat. Since that report, research on the California spotted owl has continued with much of the new information concentrated in five areas: population trends, barred owl (Strix varia) invasion, climate effects, foraging habitat, and owl response to fire.

  4. Insect-foraging in captive owl monkeys (Aotus nancymaae).

    PubMed

    Wolovich, Christy K; Rivera, Jeanette; Evans, Sian

    2010-08-01

    Whereas the diets of diurnal primate species vary greatly, almost all nocturnal primate species consume insects. Insect-foraging has been described in nocturnal prosimians but has not been investigated in owl monkeys (Aotus spp.). We studied 35 captive owl monkeys (Aotus nancymaae) in order to describe their foraging behavior and to determine if there were any age or sex differences in their ability to capture insect prey. Because owl monkeys cooperate in parental care and in food-sharing, we expected social interactions involving insect prey. We found that owl monkeys most often snatched flying insects from the air and immobilized crawling insects against a substrate using their hands. Immatures and adult female owl monkeys attempted to capture prey significantly more often than did adult males; however, there was no difference in the proportion of attempts that resulted in capture. Social interactions involving prey appeared similar to those with provisioned food, but possessors of prey resisted begging attempts more so than did possessors of other food. Owl monkeys attempted to capture prey often (mean = 9.5 +/- 5.8 attempts/h), and we speculate that the protein and lipid content of captured prey is important for meeting the metabolic demands for growth and reproduction. (c) 2010 S. Karger AG, Basel.

  5. Moving Objects in the Barn Owl's Auditory World.

    PubMed

    Langemann, Ulrike; Krumm, Bianca; Liebner, Katharina; Beutelmann, Rainer; Klump, Georg M

    2016-01-01

    Barn owls are keen hunters of moving prey. They have evolved an auditory system with impressive anatomical and physiological specializations for localizing their prey. Here we present behavioural data on the owl's sensitivity for discriminating acoustic motion direction in azimuth that, for the first time, allow a direct comparison of neuronal and perceptual sensitivity for acoustic motion in the same model species. We trained two birds to report a change in motion direction within a series of repeating wideband noise stimuli. For any trial the starting point, motion direction, velocity (53-2400°/s), duration (30-225 ms) and angular range (12-72°) of the noise sweeps were randomized. Each test stimulus had a motion direction being opposite to that of the reference stimuli. Stimuli were presented in the frontal or the lateral auditory space. The angular extent of the motion had a large effect on the owl's discrimination sensitivity allowing a better discrimination for a larger angular range of the motion. In contrast, stimulus velocity or stimulus duration had a smaller, although significant effect. Overall there was no difference in the owls' behavioural performance between "inward" noise sweeps (moving from lateral to frontal) compared to "outward" noise sweeps (moving from frontal to lateral). The owls did, however, respond more often to stimuli with changing motion direction in the frontal compared to the lateral space. The results of the behavioural experiments are discussed in relation to the neuronal representation of motion cues in the barn owl auditory midbrain.

  6. Evoked cochlear potentials in the barn owl.

    PubMed

    Köppl, Christine; Gleich, Otto

    2007-06-01

    Gross electrical responses to tone bursts were measured in adult barn owls, using a single-ended wire electrode placed onto the round window. Cochlear microphonic (CM) and compound action potential (CAP) responses were evaluated separately. Both potentials were physiologically vulnerable. Selective abolishment of neural responses at high frequencies confirmed that the CAP was of neural origin, while the CM remained unaffected. CAP latencies decreased with increasing stimulus frequency and CAP amplitudes were correlated with known variations in afferent fibre numbers from the different papillar regions. This suggests a local origin of the CAP along the tonotopic gradient within the basilar papilla. The audiograms derived from CAP and CM threshold responses both showed a broad frequency region of optimal sensitivity, very similar to behavioural and single-unit data, but shifted upward in absolute sensitivity. CAP thresholds rose above 8 kHz, while CM responses showed unchanged sensitivity up to 10 kHz.

  7. Communication of male quality in owl hoots.

    PubMed

    Hardouin, Loïc A; Reby, David; Bavoux, Christian; Burneleau, Guy; Bretagnolle, Vincent

    2007-04-01

    The evolution of communication through intrasexual selection is expected to lead signalers to transmit honest information on their fighting ability. Here we studied the information encoded in the acoustic structure of the territorial calls of a nocturnal raptor. During territorial contests, male scops owls give hoots composed of a downward frequency shift followed by a stable plateau. We found that the frequency of the hoot was negatively correlated with the body weight of the vocalizer. We shifted the frequency contour of natural hoots in order to create resynthesized calls corresponding to individuals of varying body weight and used these stimuli in playback experiments simulating an intrusion into the territory of established breeders. Territory owners responded less intensely when they heard hoots simulating heavier intruders, and males with heavier apparent weight tended to give hoots with a lower plateau in response to playbacks simulating heavier intruders.

  8. Toward instrumentation for ELTs: the OWL case

    NASA Astrophysics Data System (ADS)

    Monnet, Guy; D'Odorico, Sandro

    2004-09-01

    Based on expected Science Drivers for a 60 to 100-m diameter OWL-class telescope, we derive the basic instrumental capabilities that are needed to address them effectively. They come in three flavors -viz. an extremely high-contrast fully diffraction-limited spectro-imager, a cryogenic AO-assisted imager and multi-integral field spectrometer. Their highest priority wavelength range lies in the near-IR. In terms of size and technical requirements, these instruments belong to a quite similar class than instruments currently being developed for the 8-10 m telescopes. This places them hopefully in the feasible category, even if already rather challenging. A big caveat however is that enlarging the imaging field or the spectrometer multiplex would require large clusters of these basic "bricks". The requirements on the adaptive optics correction are stringent and call for a close and careful integration between the telescope adaptive optics systems and the instruments. We also introduce here, as a relevant example of a new observational strategy, an instrument focused on a specific scientific program - the direct measurement of the acceleration of the Universe at different epochs via the Lyα forest in QSO spectra. Being able to host dedicated facilities of this type, used for a specific observing programs in a CERN experiment-like fashion, is deemed essential to ensure that the giant telescopes of the future get and stay at the cutting edge of research in the next decade and beyond. Finally, we comment briefly on the articulation between the development of generic instrument concepts for ELTs in the frame of the European ELT Design Study and their adaptation to the OWL case.

  9. Species richness, relative abundance, and habitat associations of nocturnal birds along the rio grande in Southern texas

    USGS Publications Warehouse

    Skoruppa, M.K.; Woodin, M.C.; Blacklock, G.

    2009-01-01

    The segment of the Rio Grande between International Falcon Reservoir and Del Rio, Texas (distance ca. 350 km), remains largely unexplored ornithologically. We surveyed nocturnal birds monthly during February-June 1998 at 19 stations along the Rio Grande (n = 6) and at upland stock ponds (n = 13) in Webb County, Texas. We conducted 10-min point counts (n = 89) after sunset and before moonset. Four species of owls and five species of nightjars were detected. Nightjars, as a group, were nearly five limes more abundant (mean number/count = 2.63) than owls (mean number = 0.55). The most, common owl, the great horned owl (Bubo virginianus), had a mean number of 0.25/point count. The mean for elf owls (Micrathene whitneyi) was 0.16/point count. The most common nightjars were the common poorwill (Phalaenoptilus nuttallii; 1.21/point count) and lesser nighthawk (Chordeiles acutipennir, 1.16/point count). Survey sites on the river supported more species (mean = 2.2) than did upland stock ponds (mean = 1.4). However, only one species (common pauraque, Nyctidromus albicollis) showed a preference for the river sites. Our results establish this segment of the Rio Grande in southern Texas as an area of high diversity of nightjars in the United States, matched (in numbers of species) only by southeastern Arizona and southwestern New Mexico.

  10. Landscape features influence postrelease predation on endangered black-footed ferrets

    USGS Publications Warehouse

    Poessel, S.A.; Breck, S.W.; Biggins, D.E.; Livieri, T.M.; Crooks, K.R.; Angeloni, L.

    2011-01-01

    Predation can be a critical factor influencing recovery of endangered species. In most recovery efforts lethal and nonlethal influences of predators are not sufficiently understood to allow prediction of predation risk, despite its importance. We investigated whether landscape features could be used to model predation risk from coyotes (Canis latrans) and great horned owls (Bubo virginianus) on the endangered black-footed ferret (Mustela nigripes). We used location data of reintroduced ferrets from 3 sites in South Dakota to determine whether exposure to landscape features typically associated with predators affected survival of ferrets, and whether ferrets considered predation risk when choosing habitat near perches potentially used by owls or near linear features predicted to be used by coyotes. Exposure to areas near likely owl perches reduced ferret survival, but landscape features potentially associated with coyote movements had no appreciable effect on survival. Ferrets were located within 90 m of perches more than expected in 2 study sites that also had higher ferret mortality due to owl predation. Densities of potential coyote travel routes near ferret locations were no different than expected in all 3 sites. Repatriated ferrets might have selected resources based on factors other than predator avoidance. Considering an easily quantified landscape feature (i.e., owl perches) can enhance success of reintroduction efforts for ferrets. Nonetheless, development of predictive models of predation risk and management strategies to mitigate that risk is not necessarily straightforward for more generalist predators such as coyotes. ?? 2011 American Society of Mammalogists.

  11. Hematologic parameters in raptor species in a rehabilitation setting before release.

    PubMed

    Black, Peter A; McRuer, David L; Horne, Leigh-Ann

    2011-09-01

    To be considered for release, raptors undergoing rehabilitation must have recovered from their initial injury in addition to being clinically healthy. For that purpose, a good understanding of reference hematologic values is important in determining release criteria for raptors in a rehabilitation setting. In this study, retrospective data were tabulated from clinically normal birds within 10 days of release from a rehabilitation facility. Hematologic values were compiled from 71 red-tailed hawks (Buteo jamaicensis), 54 Eastern screech owls (Megascops asio), 31 Cooper's hawks (Accipiter cooperii), 30 great-horned owls (Bubo virginianus), 28 barred owls (Strix varia), 16 bald eagles (Haliaeetus leucocephalus), and 12 broad-winged hawks (Buteo platypterus). Parameters collected included a white blood cell count and differential, hematocrit, and total protein concentration. Comparisons were made among species and among previously published reports of reference hematologic values in free-ranging birds or permanently captive birds. This is the first published report of reference values for Eastern screech owls, barred owls, and broad-winged hawks; and the first prerelease reference values for all species undergoing rehabilitation. These data can be used as a reference when developing release criteria for rehabilitated raptors.

  12. Plague

    MedlinePlus

    ... Tests Tests that may be done include: Blood culture Culture of lymph node aspirate (fluid taken from an affected lymph node or bubo) Sputum culture Treatment People with the plague need immediate treatment. ...

  13. Groin lump

    MedlinePlus

    ... lymphadenopathy; Localized lymphadenopathy - groin; Bubo; Lymphadenopathy - groin Images Lymphatic system Swollen lymph nodes in the groin References ... and the A.D.A.M. Editorial team. Lymphatic Diseases Read more Latest Health News Read more ...

  14. [Occurrence of parasites in indigenous birds of prey and owls].

    PubMed

    Lierz, M; Göbel, T; Schuster, R

    2002-01-01

    In the present paper a general overview on parasites in birds of prey and owls is given. This part is followed by a study investigating the prevalences and species of parasites in free-ranging birds of prey and owls in Berlin and Brandenburg State, Germany. Over a one year period, 84 birds of prey and owls of the following species were examined for the presence of endo- and ectoparasites: Common Buzzard (Buteo buteo) (n = 32), Kestrel (Falco tinnunculus) (n = 20), Sparrowhawk (Accipiter nisus) (n = 9), Goshawk (Accipiter gentilis) (n = 8), Black Kite (Milvus migrans) (n = 4), Peregrine Falcon (Falco peregrinus) (n = 3), Marsh Harrier (Circus aeruginosus) (n = 1), White-tailed-Sea Eagle (Haliaeetus albicilla) (n = 1), Tawny Owl (Strix aluco) (n = 4), Long-eared Owl (Asio otus) (n = 1) and Barn Owl (Tyto alba) (n = 1). In 97.6% of the cases, ectoparasites (feather mites and hippoboscid flies) were found. Especially eyasses (93.3%) were positive for hippoboscid flies. Trichomonas was detected in 28.6% of all birds of prey and owls examined. A prevalence of 100% was established in the Sparrow Hawks as well as Peregrine Falcons. Leucozytozoon sp. and Hemoproteus sp. as blood parasites were found in 26.9% of the birds in total. Common Buzzards showed the highest prevalence (44.8%). 58.3% of birds examined were positive for endoparasites. Flukes were found in 16.7%, tapeworms in 14.3%, round-worms in 48.8% and acanthocephales in 2.4% of the cases. Interestingly, Tylodelphis clavata (in a Common Buzzard) and Hovorkonema variegatum (in a Goshawk) were found for the first time in raptors. The results of this study underline the importance of a parasitological examination in the process of raptor rehabilitation.

  15. Evidence for recent populations bottlenecks in northern spotted owls (Strix occidentalis Caurina)

    Treesearch

    W.Chris Funk; Eric D. Forsman; Matthew Johnson; Thomas D. Mullins; Susan M.. Haig

    2009-01-01

    The northern spotted owl (Strix occidentalis caurina) is one of the most controversial threatened subspecies ever listed under the US Endangered Species Act. Despite protection of its remaining forest habitat, recent field studies show continued declines of northern spotted owls. One potential threat to northern spotted owls which has not yet been...

  16. Book review: Peeters, H. 2007. Field guide to owls of California and the West

    Treesearch

    Eric D. Forsman

    2010-01-01

    Field Guide to Owls of California and the West. Written primarily for nonprofessionals,this little field guide is a treasure trove of published and unpublished information on the natural history and distribution of owls in the western United States. It covers just about everything you could want to know about owls, from why they take dust baths, to facultative...

  17. Radio telemetry methods for studying spotted owls in the Pacific Northwest.

    Treesearch

    J.H. Guetterman; J.A. Burns; J.A. Reid; R.B. Horn; C.C. Foster

    1991-01-01

    The paper is a practical guide to field methodology for conducting a radio telemetry study of spotted owls (Strix occidentalis) in mountainous terrain. It begins with a synopsis of spotted owl biology and basic telemetry. The criteria used to select which owls will carry transmitters are discussed as are location and capture methods. Instructions...

  18. Orthopaedic Web Links (OWL): a way to find professional orthopaedic information on the internet.

    PubMed

    Clough, J F M; Veillette, C J H

    2011-07-01

    Finding useful high-grade professional orthopaedic information on the Internet is often difficult. Orthopaedic Web Links (OWL) is a searchable database of vetted online orthopaedic resources. OWL uses a subject directory (OWL Directory) and a custom search engine (OWL Web) to provide a list of resources. The most effective way to find readily accessible, full text on-subject material suitable for education of an orthopaedic surgeon or trainee has not been defined. We therefore (1) proposed a method for selecting topics and evaluating searches and (2) compared the search results from an orthopaedic-specific directory (OWL Directory), a custom search engine (OWL Web), and standard Google searches. A scoring system for evaluation of the search results was developed for standardized comparison. Single words and sets of three words from randomly selected examination questions provided the search strings to compare the three strategies. For single keyword searches, the OWL Directory scored highest (16.4/50) of the three methods. For the three keywords searches, OWL Web had the highest mean score (26.0/50), followed by Google (22.8/50), and the OWL Directory (1.0/50). OWL Web searches had higher scores than Google searches, while returning 800 times fewer search results. The OWL Directory of orthopaedic subjects on the Internet provides a simple browsable category structure to find information. The OWL Web search engine scored higher than Google and resulted in a greater proportion of valid, on-subject, and accessible resources in the search results.

  19. 77 FR 12985 - Proposed Revised Habitat for the Spotted Owl: Minimizing Regulatory Burdens

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-05

    ...#0;#0; ] Memorandum of February 28, 2012 Proposed Revised Habitat for the Spotted Owl: Minimizing... Department of the Interior (Department) proposed critical habitat for the northern spotted owl. The proposal... should be designated as critical habitat for the spotted owl, based on a full evaluation of all key...

  20. 3 CFR - Proposed Revised Habitat for the Spotted Owl: Minimizing Regulatory Burdens

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 3 The President 1 2013-01-01 2013-01-01 false Proposed Revised Habitat for the Spotted Owl..., 2012 Proposed Revised Habitat for the Spotted Owl: Minimizing Regulatory Burdens Memorandum for the...) proposed critical habitat for the northern spotted owl. The proposal is an initial step in gathering...

  1. Chapter 16. Conservation status of great gray owls in the United States

    Treesearch

    Gregory D. Hayward

    1994-01-01

    Previous chapters outlined the biology and ecology of great gray owls as well as the ecology of this species in the western United States. That technical review provides the basis to assess the current conservation status of great gray owls in the United States. Are populations of great gray owls in the United States currently threatened? Are current land management...

  2. Seasonal distribution of the Great Gray Owl (Strix nebulosa) in Southwestern Alberta

    Treesearch

    Douglas M. Collister

    1997-01-01

    Great Gray Owls (Strix nebulosa) have been banded and monitored west of Calgary in the foothills of Alberta from 1986 to 1996. Thirty-six adult owls have been banded: 16 males, 16 females and 4 of unknown sex. Great Gray Owls were captured during every month except August and October although the majority (56 percent) were banded from March-May (n=18...

  3. Monitoring Boreal Forest Owls in Ontario using tape playback surveys with volunteers

    Treesearch

    Charles M. Francis; Michael S. W. Bradstreet

    1997-01-01

    Long Point Bird Observatory ran pilot surveys in 1995 and 1996 to monitor boreal forest owls in Ontario using roadside surveys with tape playback of calls. A minimum of 791 owls on 84 routes in 1995, and 392 owls on 88 routes in 1996; nine different species were detected. Playback improved the response rate for Barred (Strix varia), Boreal (...

  4. Biology and conservation of owls of the Northern Hemisphere: 2nd International symposium

    Treesearch

    James R. Duncan; David H. Johnson; Thomas H. Nicholls

    1997-01-01

    The proceeding contains 91 papers authored by 143 people from 13 countries covering biology, ecology, monitoring, habitat-use, status conservation, education, genetics, toxicology, diet, migration, mortality and related topics concerning owls of the Northern Hemisphere. Thirty-three owl species are discussed. Information presented will be useful in owl conservation,...

  5. Comparative study of general public owl knowledge in Costa Rica, Central America and Malawi, Africa

    Treesearch

    Paula A. Enriquez; Heimo Mikkola

    1997-01-01

    The public knowledge of owls in Central America and Africa was compared based on 162 interviews in Costa Rica and 147 in Malawi. General knowledge of owls included: species, common names, habitats, food, and calls, and was quite similar in both study areas. In Malawi, more than 90 percent of the respondents connected owls with bad luck, witchcraft, and death. In Costa...

  6. Synthesis and interpretation of California spotted owl research within the context of public forest management

    Treesearch

    M. Zachariah Peery; R.J. Gutiérrez; Patricia N. Manley; Peter Stine; Malcolm P. North

    2017-01-01

    In this chapter, we synthesize the information presented in the preceding chapters of this assessment of the California spotted owl (Strix occidentalis occidentalis) and provide a scientific appraisal of its implications for forest management and owl conservation. We focus on the key scientific findings since the 1992 California spotted owl...

  7. Modeling co-occurrence of northern spotted and barred owls: accounting for detection probability differences

    Treesearch

    Larissa L. Bailey; Janice A. Reid; Eric D. Forsman; James D. Nichols

    2009-01-01

    Barred owls (Strix valia) have recently expanded their range and now encompass the entire range of the northern spotted owl (Strix ocddentalis caulina). This expansion has led to two important issues of concern for management of northern spotted owls: (1) possible competitive interactions between the two species that could...

  8. 76 FR 37141 - Notice of Availability for Comment: Draft Recovery Plan, First Revision; Mexican Spotted Owl

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-24

    ...; Mexican Spotted Owl AGENCY: Fish and Wildlife Service, Interior. ACTION: Notice of availability; request... recovery plan, first revision, for the Mexican Spotted Owl (Strix occidentalis lucida) under the Endangered... will also accept any new information on the status of the Mexican spotted owl throughout its range...

  9. Barred owl space use and habitat selection in the eastern Cascades, Washington

    Treesearch

    Peter J. Singleton; John F. Lehnkuhl; William L. Gaines; Scott A. Graham

    2010-01-01

    Competition with barred owls (Strix varia varia) is an important factor contributing to the continued decline of threatened northern spotted owl (Strix occidentalis caurina) populations in the Pacific Northwest, USA, but basic information on habitat selection and space use patterns of barred owls is lacking for much of the...

  10. Chapter 1. Approach: The flammulated, boreal, and great gray owl assessments

    Treesearch

    Gregory D. Hayward

    1994-01-01

    This forest owl conservation assessment focuses on three species of forest owls that occur on national forest lands in the United States. Sixteen other species of owls also regularly breed in the United States, but these three species were designated "sensitive" on forests in more than one region of the Forest Service in 1992. Within the National Forest...

  11. A method for locating Barred Owl (Strix varia) nests in the southern boreal forest of Saskatchewan

    Treesearch

    Shanna D. Frith; Kurt M. Mazur; Paul C. James

    1997-01-01

    Barred Owl (Strix varia) nests are often very difficult to locate. We developed a method for locating Barred Owl nests within the boreal forest of central Saskatchewan, Canada. During the nesting period, we located pairs of Barred Owls through call-playback surveys. We returned to the survey location at sunset and listened for vocalizations from the...

  12. Detecting West Nile virus in owls and raptors by an antigen-capture assay.

    PubMed

    Gancz, Ady Y; Campbell, Douglas G; Barker, Ian K; Lindsay, Robbin; Hunter, Bruce

    2004-12-01

    We evaluated a rapid antigen-capture assay (VecTest) for detection of West Nile virus in oropharyngeal and cloacal swabs, collected at necropsy from owls (N = 93) and raptors (N = 27). Sensitivity was 93.5%-95.2% for northern owl species but <42.9% for all other species. Specificity was 100% for owls and 85.7% for raptors.

  13. Habitat selection by owls in a seasonal semi-deciduous forest in southern Brazil.

    PubMed

    Menq, W; Anjos, L

    2015-11-01

    This paper tested the hypothesis that the structural components of vegetation have impact over the distribution of owl species in a fragment of a semi-deciduous seasonal forest. This paper also determined which vegetation variables contributed to the spatial distribution of owl species. It was developed in the Perobas Biological Reserve (PBR) between September and December 2011. To conduct the owl census, a playback technique was applied at hearing points distributed to cover different vegetation types in the study area. A total of 56 individual owls of six species were recorded: Tropical Screech-Owl (Megascops choliba), Black-capped Screech-Owl (Megascops atricapilla), Tawny-browed Owl (Pulsatrix koeniswaldiana), Ferruginous Pygmy-Owl (Glaucidium brasilianum), Mottled Owl (Strix virgata) and Stygian Owl (Asio stygius). The results suggest that the variables of vegetation structure have impact on the occurrence of owls. The canopy height, the presence of hollow trees, fallen trees and glades are the most important structural components influencing owl distribution in the sampled area.

  14. Clinical findings, lesions, and viral antigen distribution in great gray owls (Strix nebulosa) and barred owls (Strix varia) with spontaneous West Nile virus infection.

    PubMed

    Lopes, Hugo; Redig, Pat; Glaser, Amy; Armien, Anibal; Wünschmann, Arno

    2007-03-01

    West Nile Virus (WNV) infection manifests itself clinically a nd pathologically differently in various species of birds. The clinicopathologic findings and WNV antigen tissue distribution of six great gray owls (Strix nebulosa) and two barred owls (Strix varia) with WNV infection are described in this report. Great gray owls usually live in northern Canada, whereas the phylogenetically related barred owls are native to the midwestern and eastern United States and southern Canada. Naturally acquired WNV infection caused death essentially without previous signs of disease in the six great gray owls during a mortality event. Lesions of WNV infection we re dominated by hepatic and splenic necrosis, with evidence o f disseminatedintravascular coagulation in the great gray owls. WNV antigen was widely distributed in th e organs of the great gray owls and appeared totarget endothelial cells, macrophages, and hepatocytes. The barred owls represented two sporadic cases. They had neurologic disease with mental dullness that led to euthanasia. These birds had mild to moderate lymphoplasmacytic encephalitis with glial nodules and lymphoplasmacytic pectenitis. WNV antigen was sparse in barred owls and only present in a few brain neurons and renaltubular epithelial cells. The cause of the different manifestations of WNV disease in these fairly closely related owl species is uncertain.

  15. Sound localization by barn owls in a simulated echoic environment.

    PubMed

    Spitzer, Matthew W; Takahashi, Terry T

    2006-06-01

    We examined the accuracy and precision with which the barn owl (Tyto alba) turns its head toward sound sources under conditions that evoke the precedence effect (PE) in humans. Stimuli consisted of 25-ms noise bursts emitted from two sources, separated horizontally by 40 degrees, and temporally by 3-50 ms. At delays from 3 to 10 ms, head turns were always directed at the leading source, and were nearly as accurate and precise as turns toward single sources, indicating that the leading source dominates perception. This lead dominance is particularly remarkable, first, because on some trials, the lagging source was significantly higher in amplitude than the lead, arising from the directionality of the owl's ears, and second, because the temporal overlap of the two sounds can degrade the binaural cues with which the owl localizes sounds. With increasing delays, the influence of the lagging source became apparent as the head saccades became increasingly biased toward the lagging source. Furthermore, on some of the trials at delays > or = 20 ms, the owl turned its head, first, in the direction of one source, and then the other, suggesting that it was able to resolve two separately localizable sources. At all delays <50 ms, response latencies were longer for paired sources than for single sources. With the possible exception of response latency, these findings demonstrate that the owl exhibits precedence phenomena in sound localization similar to those in humans and cats, and provide a basis for comparison with neurophysiological data.

  16. A spatial analysis of the Burrowing Owl (Speotyto cunicularia) population in Santa Clara County, California, using a geographic information system

    Treesearch

    Janice Taylor Buchanan

    1997-01-01

    A small population of Burrowing Owls (Speotyto cunicularia) is found in the San Francisco Bay Area, particularly in Santa Clara County. These owls utilize habitat that is dispersed throughout this heavily urbanized region. In an effort to establish a conservation plan for Burrowing Owls in Santa Clara County, a spatial analysis of owl distribution...

  17. Effectiveness of broadcast surveys in determining habitat use of Ferruginous Pygmy-owls (Glaucidium brasilianum) in southern Texas

    Treesearch

    Glenn A. Proudfoot; Jody L. Mays; Sam L. Beasom; Ralph Bingham

    1997-01-01

    We compared habitat information obtained from tracking 12 radio-tagged Ferruginous Pygmy-owls (Glaucidium brasilianum) (hereafter referred to as pygmy-owls) in southern Texas during 1995 and similar information from pygmy-owl response points to evaluate the effectiveness of broadcast surveys in determining pygmy-owl habitat use.

  18. Habitat use and movements of breeding male Boreal Owls (Aegolius funereus) in northeast Minnesota as determined by radio telemetry

    Treesearch

    William H. Lane; David E. Andersen; Thomas H. Nicholls

    1997-01-01

    To determine habitat use and movements of male Boreal Owls (Aegolius funereus) in northeast Minnesota, we monitored 10 radio-equipped owls from 1990-1992. We used mist nets, bal-chartris, and the taped playback recording of the primary song of the male Boreal Owl to trap territorial male owls during the springtime breeding season.

  19. Otoacoustic interrelationships of the barn owl

    NASA Astrophysics Data System (ADS)

    Bergevin, Christopher; Manley, Geoffrey A.; Köppl, Christine

    2015-12-01

    Significant debate still exists about the biophysical mechanisms at work in otoacoustic emission (OAE) generation and how such may differ between mammals and non-mammals given gross morphological differences (e.g., existence of basilar membrane traveling waves, degree of tectorial membrane coupling). To further elucidate general principles at work, we examined the barn owl for interrelationships between spontaneous emissions (SOAEs) and those evoked using a single tone (SFOAEs). First, most ears exhibited SOAEs as a stable periodic `rippling' whose peak-to-peak spacing was relatively constant (˜0.4 kHz). Some ears showed substantially larger narrowband peaks, although their statistical distributions were highly noisy. Second, significant interactions between a low-level tone and SOAE activity were observed via an interference pattern as the tone frequency was swept. Using a suppression paradigm to extract SFOAEs as the residual, the magnitude exhibited a stable pattern of peaks and valleys unique to each ear. Third, SFOAE phase exhibited significant accumulation as frequency was swept, with a phase-gradient delay of approximately 2 ms that was constant across frequency. The amount of SFOAE phase accumulation between adjacent SOAE peaks tended to cluster about an integral number of cycles, as previously observed for humans. Taken together, our data suggest that the principles underlying how active hair cells work together (e.g., entrainment, phase coherence) are shared between widely different inner ear morphologies, leading to the generation of OAEs with similar properties.

  20. The type specimens of Hekstra's owl

    USGS Publications Warehouse

    Browning, M.R.

    1989-01-01

    Twenty-four new subspecies of New World owls of the genus Otus were named in a paper by Hekstra (1982b) issued 17 December 1982. These same new names also appeared in Hekstra's (1982a) unpublished thesis. The holotypes of the new taxa are in 10 different collections, most of which are in the United States. Incorrect information was published with regard to museum designation, museum number, and collecting locality of many of the holotypes. I here list the holotypes with their correct specimen label data. The species names are here presented in the sequence proposed by Marshall & King (1988). The subspecies are generally arranged from north to south. The type localities given are standardized, and the spellings are corrected where required. Abbreviations for museum designations are given under acknowledgments. The numbers following the names refer to the pages where the descriptions were given (Hekstra 1982b). Several of the scientific names proposed were spelled incorrectly and these have been emended in accord with Article 31c and Appendix D of the International Code (International Commission on Zoological Nomenclature 1985). Taxonomic comments are appended for a small number of Hekstra's proposed taxa. The remaining forms he named require further study.

  1. Do owls use torpor? Winter thermoregulation in free-ranging pearl-spotted owlets and African scops-owls.

    PubMed

    Smit, Ben; McKechnie, Andrew E

    2010-01-01

    Numerous avian taxa use torpor, which involves pronounced reductions in body temperature (T(b)) to below normothermic levels. However, the occurrence of this phenomenon in owls (Strigidae) remains largely unknown. We investigated winter patterns of thermoregulation in the crepuscular 80-g pearl-spotted owlet Glaucidium perlatum and the strictly nocturnal 61-g African scops-owl Otus senegalensis by obtaining telemetric measurements of skin temperature (T(skin)) from free-ranging individuals in the Kalahari Desert of southern Africa. Pearl-spotted owlets remained homeothermic throughout the study period, whereas African scops-owls routinely used shallow torpor, with T(skin) reduced by 3.3 degrees -8.6 degrees C (pooled mean, 5.3+/- 1.1 degrees C) below normothermic levels for 3-4 h after sunrise. The mean lowest T(skin) recorded in three African scops-owl individuals was 29.0 degrees C +/- 0.1 degrees C. The thermoregulatory differences between these two species may be related to their diets and activity patterns. African scops-owls are almost exclusively insectivorous and experience a marked reduction in food availability on cold winter nights. In contrast, pearl-spotted owlets have more flexible activity patterns and include larger or diurnal vertebrate prey in their diet.

  2. Serologic evidence of exposure of raptors to influenza A virus.

    PubMed

    Redig, Patrick T; Goyal, Sagar M

    2012-06-01

    Serum or plasma samples from raptors that prey or scavenge upon aquatic birds were tested by a commercially available blocking enzyme-linked immunosorbent assay for the evidence of antibodies to influenza A virus. Samples were taken from birds (n = 616) admitted to two rehabilitation centers in the United States. In addition, samples from 472 migrating peregrine falcons (Falco peregrinus) trapped on autumnal and vernal migrations for banding purposes were also tested. Only bald eagles were notably seropositive (22/406). One each of peregrine falcon, great horned owl (Bubo virginianus), and Cooper's hawk (Accipiter cooperi) from a total of 472, 81, and 100, respectively, were also positive. None of the turkey vultures (n = 21) or black vultures (n = 8) was positive. No clinical signs referable to avian influenza were seen in any bird at the time of capture. These data indicate that, among raptors, bald eagles do have exposure to influenza A viruses.

  3. Case histories of bald eagles and other raptors killed by organophosphorus insecticides topically applied to livestock

    USGS Publications Warehouse

    Henny, C.J.; Kolbe, E.J.; Hill, E.F.; Blus, L.J.

    1987-01-01

    Since 1982 when secondary poisoning of a red-tailed hawk (Buteo jamaicensis) was documented following the recommended use of famphur applied topically to cattle, the Patuxent Wildlife Research Center has tested dead birds of prey for poisoning by famphur and other pour-on organophosphorus (OP) insecticides. Brain cholinesterase (ChE) activity was first determined, then if ChE was depressed greater than or equal to 50%, stomach and/or crop contents were evaluated for anti-ChE compounds. This report presents the circumstances surrounding the OP-caused deaths of eight bald eagles (Haliaeetus leucocephalus), two red-tailed hawks, and one great horned owl (Bubo virginianus) between March 1984 and March 1985. OP poisoning of raptors by pour-on insecticides in the United States is widespread, but its magnitude is unknown.

  4. Case histories of bald eagles and other raptors killed by organophosphorus insecticides topically applied to livestock.

    PubMed

    Henny, C J; Kolbe, E J; Hill, E F; Blus, L J

    1987-04-01

    Since 1982 when secondary poisoning of a red-tailed hawk (Buteo jamaicensis) was documented following the recommended use of famphur applied topically to cattle, the Patuxent Wildlife Research Center has tested dead birds of prey for poisoning by famphur and other pour-on organophosphorus (OP) insecticides. Brain cholinesterase (ChE) activity was first determined, then if ChE was depressed greater than or equal to 50%, stomach and/or crop contents were evaluated for anti-ChE compounds. This report presents the circumstances surrounding the OP-caused deaths of eight bald eagles (Haliaeetus leucocephalus), two red-tailed hawks, and one great horned owl (Bubo virginianus) between March 1984 and March 1985. OP poisoning of raptors by pour-on insecticides in the United States is widespread, but its magnitude is unknown.

  5. Morphometry of auricular feathers of barn owls (Tyto alba).

    PubMed

    Koch, U R; Wagner, H

    2002-02-01

    In all owl species, the facial plumage forms a parabolic dish, the facial ruff, which is most conspicuous in the the barn owl (Tyto alba). The center of the ruff is formed by auricular feathers. Such feathers are also found on the preaural flaps which cover the ear openings, and in the region of the beak. In this study, we compare the different types of auricular feathers of the barn owl with contour feathers from the neck. Auricular feathers are characterised by an open vane structure and fewer barbs as compared to contour feathers. Auricular feathers also have fewer distal and proximal barbules than contour feathers. The open vane of the auricular feather results from an acute angle between the barb and the basis of the barbules, and from the extension of the pennula parallel to the barbs. These reductions are differently expressed in the three different types of auricular feathers investigated here and correspond with their function (protecting the ruff from dust).

  6. First observed instance of polygyny in Flammulated Owls

    USGS Publications Warehouse

    Linkhart, B.D.; Evers, E.M.; Megler, J.D.; Palm, E.C.; Salipante, C.M.; Yanco, S.W.

    2008-01-01

    We document the first observed instance of polygyny in Flammulated Owls (Otus flammeolus) and the first among insectivorous raptors. Chronologies of the male's two nests, which were 510 m apart, were separated by nearly 2 weeks. Each brood initially consisted of three owlets, similar to the mean brood size in monogamous pairs. The male delivered considerably fewer prey to the secondary nest, compared with prey-delivery rates at nests of monogamous males during the nestling period. Evidence suggested that all owlets fledged from the primary brood, but only one fledged from the secondary brood. We were uncertain of the cause of polygyny, but a possible explanation is the Hayman Fire shifted the operational sex ratio of the owls in favor of females. The extent of polygyny in Flammulated Owls may be limited by costs to the reproductive success of secondary females.

  7. Complex state-dependent games between owls and gerbils.

    PubMed

    Berger-Tal, Oded; Mukherjee, Shomen; Kotler, Burt P; Brown, Joel S

    2010-03-01

    Predator-prey interactions are often behaviourally sophisticated games in which the predator and prey are players. Past studies teach us that hungrier prey take higher risks when foraging and that hungrier predators increase their foraging activity and are willing to take higher risks of injury. Yet no study has looked at the simultaneous responses of predator and prey to their own and each other's hunger levels in a controlled environment. We looked for evidence of a state-dependent game between predators and their prey by simultaneously manipulating the hunger state of barn owls, and Allenby's gerbils as prey. The owls significantly increased their activity when hungry. However, they did not appear to respond to changes in the hunger state of the gerbils. The gerbils reacted strongly to the owls' state, as well as to their own state when the risk was perceived as high. Our study shows that predator-prey interactions give rise to a complex state-dependent game.

  8. Morphological Variations of Leading-Edge Serrations in Owls (Strigiformes)

    PubMed Central

    Weger, Matthias; Wagner, Hermann

    2016-01-01

    Background Owls have developed serrations, comb-like structures, along the leading edge of their wings. Serrations were investigated from a morphological and a mechanical point of view, but were not yet quantitatively compared for different species. Such a comparative investigation of serrations from species of different sizes and activity patterns may provide new information about the function of the serrations. Results Serrations on complete wings and on tenth primary remiges of seven owl species were investigated. Small, middle-sized, and large owl species were investigated as well as species being more active during the day and owls being more active during the night. Serrations occurred at the outer parts of the wings, predominantly at tenth primary remiges, but also on further wing feathers in most species. Serration tips were oriented away from the feather rachis so that they faced into the air stream during flight. The serrations of nocturnal owl species were higher developed as demonstrated by a larger inclination angle (the angle between the base of the barb and the rachis), a larger tip displacement angle (the angle between the tip of the serration and the base of the serration) and a longer length. Putting the measured data into a clustering algorithm yielded dendrograms that suggested a strong influence of activity pattern, but only a weak influence of size on the development of the serrations. Conclusions Serrations are supposed to be involved in noise reduction during flight and also depend on the aerodynamic properties that in turn depend on body size. Since especially nocturnal owls have to rely on hearing during prey capture, the more pronounced serrations of nocturnal species lend further support to the notion that serrations have an important function in noise reduction. The differences in shape of the serrations investigated indicate that a silent flight requires well-developed serrations. PMID:26934104

  9. Socialization of adult owl monkeys (Aotus sp.) in Captivity.

    PubMed

    Williams, Lawrence E; Coke, C S; Weed, J L

    2017-01-01

    Social housing has often been recommended as one-way to address the psychological well-being of captive non-human primates. Published reports have examined methods to socialize compatible animals by forming pairs or groups. Successful socialization rates vary depending on the species, gender, and environment. This study presents a retrospective look at pairing attempts in two species of owl monkeys, Aotus nancymaae and A. azarae, which live in monogamous pairs in the wild. The results of 477 pairing attempt conducted with captive, laboratory housed owl monkeys and 61 hr of behavioral observations are reported here. The greatest success pairing these owl monkeys occurred with opposite sex pairs, with an 82% success rate. Opposite sex pairs were more successful when females were older than males. Female-female pairs were more successful than male-male (MM) pairs (62% vs 40%). Successful pairs stayed together between 3 and 7 years before the animals were separated due to social incompatibility. Vigilance, eating, and sleeping during introductions significantly predicted success, as did the performance of the same behavior in both animals. The results of this analysis show that it is possible to give captive owl monkeys a social alternative even if species appropriate social partners (i.e., opposite sex partners) are not available. The focus of this report is a description of one potential way to enhance the welfare of a specific new world primate, the owl monkey, under laboratory conditions. More important is how the species typical social structure of owl monkeys in nature affects the captive management of this genus. Am. J. Primatol. 79:e22521, 2017. © 2015 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  10. Gongylonema sp. infection in the scops owl (Otus scops).

    PubMed

    Esperón, Fernando; Martín, María Paz; Lopes, Francisca; Orejas, Patricia; Carrero, Laura; Muñoz, María Jesús; Alonso, Raúl

    2013-12-01

    Since 1997, it has been observed that fledging scops owls often develop necrotic plaques in their oral cavities, which in severe cases can even affect bone tissue. This condition has been defined as a necrotic oropharyngeal disease based on gross lesions. In 2011 alone, thirty-five cases were identified at the Brinzal Owl Rescue Centre (Madrid, Spain), of which four were chosen to perform a complete diagnostic study. Histopathology was carried out in three cases and cytology in one case. Using morphological traits cytology identified two larvae as third-stage larvae of a Spiruridae nematode. Histology detected parasite sections in the mucosal epithelium of the mouth of one owl. In addition, four samples of mucosal lesions were subjected to a PCR amplification of the nematode ribosomal RNA gene using a pair of universal primers, three of which were positive. Of available sequences, the sequence obtained showed the closest affinity to that of Gongylonema pulchrum (97.8-98.0%). Clinical treatment was based on supportive therapy, the daily removal of caseous material from the oral cavity and the administration of fenbendazol (50mg/kg PO for 5 days). Approximately 60% of the affected scops owls that arrived at the rescue centre in 2011 were cured and released back into the wild. Clinical, pathological and molecular findings are consistent with Gongylonema sp. infection. Since no evidence of the presence of adult parasites was found, we suggest that these scops owls should be considered as accidental hosts. This is the first description of severe Gongylonema infection in fledgling scops owls, a disease can lead to starvation and death if proper treatment is not provided. © 2013.

  11. Comparison of Plasmodium falciparum infections in Panamanian and Colombian owl monkeys.

    PubMed

    Rossan, R N; Harper, J S; Davidson, D E; Escajadillo, A; Christensen, H A

    1985-11-01

    Parameters of blood-induced infections of the Vietnam Oak Knoll, Vietnam Smith, and Uganda Palo Alto strains of Plasmodium falciparum studied in 395 Panamanian owl monkeys in this laboratory between 1976-1984 were compared with those reported from another laboratory for 665 Colombian owl monkeys, studied between 1968-1975, and, at the time, designated Aotus trivirgatus griseimembra. The virulence of these strains was less in Panamanian than in Colombian owl monkeys, as indicated by lower mortality rates of the Panamanian monkeys during the first 30 days of patency. Maximum parasitemias of the Vietnam Smith and Uganda Palo Alto strain, in Panamanian owl monkeys dying during the first 15 days of patent infection, were significantly higher than in Colombian owl monkeys. Panamanian owl monkeys that survived the primary attack had significantly higher maximum parasitemias than the surviving Colombian owl monkeys. Peak parasitemias were attained significantly earlier after patency in Panamanian than in Colombian owl monkeys, irrespective of the strain of P. falciparum. More Panamanian than Colombian owl monkeys evidenced self-limited infection after the primary attack of either the Vietnam Smith or Uganda Palo Alto strain. The duration of the primary attacks and recrudescences were significantly shorter in Panamanian than in Colombian owl monkeys. Mean peak parasitemias during recrudescence were usually higher in Panamanian owl monkeys than in Colombian monkeys. Differences of infection parameters were probably attributable, in part, to geographical origin of the two monkey hosts and parasite strains.

  12. Auditory Processing, Plasticity, and Learning in the Barn Owl

    PubMed Central

    Peña, José L.; DeBello, William M.

    2011-01-01

    The human brain has accumulated many useful building blocks over its evolutionary history, and the best knowledge of these has often derived from experiments performed in animal species that display finely honed abilities. In this article we review a model system at the forefront of investigation into the neural bases of information processing, plasticity, and learning: the barn owl auditory localization pathway. In addition to the broadly applicable principles gleaned from three decades of work in this system, there are good reasons to believe that continued exploration of the owl brain will be invaluable for further advances in understanding of how neuronal networks give rise to behavior. PMID:21131711

  13. Eye shape and retinal topography in owls (Aves: Strigiformes).

    PubMed

    Lisney, Thomas J; Iwaniuk, Andrew N; Bandet, Mischa V; Wylie, Douglas R

    2012-01-01

    The eyes of vertebrates show adaptations to the visual environments in which they evolve. For example, eye shape is associated with activity pattern, while retinal topography is related to the symmetry or 'openness' of the habitat of a species. Although these relationships are well documented in many vertebrates including birds, the extent to which they hold true for species within the same avian order is not well understood. Owls (Strigiformes) represent an ideal group for the study of interspecific variation in the avian visual system because they are one of very few avian orders to contain species that vary in both activity pattern and habitat preference. Here, we examined interspecific variation in eye shape and retinal topography in nine species of owl. Eye shape (the ratio of corneal diameter to eye axial length) differed among species, with nocturnal species having relatively larger corneal diameters than diurnal species. All the owl species have an area of high retinal ganglion cell (RGC) density in the temporal retina and a visual streak of increased cell density extending across the central retina from temporal to nasal. However, the organization and degree of elongation of the visual streak varied considerably among species and this variation was quantified using H:V ratios. Species that live in open habitats and/or that are more diurnally active have well-defined, elongated visual streaks and high H:V ratios (3.88-2.33). In contrast, most nocturnal and/or forest-dwelling owls have a poorly defined visual streak, a more radially symmetrical arrangement of RGCs and lower H:V ratios (1.77-1.27). The results of a hierarchical cluster analysis indicate that the apparent interspecific variation is associated with activity pattern and habitat as opposed to the phylogenetic relationships among species. In seven species, the presence of a fovea was confirmed and it is suggested that all strigid owls may possess a fovea, whereas the tytonid barn owl (Tyto alba

  14. Relations as patterns: bridging the gap between OBO and OWL.

    PubMed

    Hoehndorf, Robert; Oellrich, Anika; Dumontier, Michel; Kelso, Janet; Rebholz-Schuhmann, Dietrich; Herre, Heinrich

    2010-08-31

    most biomedical ontologies are represented in the OBO Flatfile Format, which is an easy-to-use graph-based ontology language. The semantics of the OBO Flatfile Format 1.2 enforces a strict predetermined interpretation of relationship statements between classes. It does not allow flexible specifications that provide better approximations of the intuitive understanding of the considered relations. If relations cannot be accurately expressed then ontologies built upon them may contain false assertions and hence lead to false inferences. Ontologies in the OBO Foundry must formalize the semantics of relations according to the OBO Relationship Ontology (RO). Therefore, being able to accurately express the intended meaning of relations is of crucial importance. Since the Web Ontology Language (OWL) is an expressive language with a formal semantics, it is suitable to de ne the meaning of relations accurately. we developed a method to provide definition patterns for relations between classes using OWL and describe a novel implementation of the RO based on this method. We implemented our extension in software that converts ontologies in the OBO Flatfile Format to OWL, and also provide a prototype to extract relational patterns from OWL ontologies using automated reasoning. The conversion software is freely available at http://bioonto.de/obo2owl, and can be accessed via a web interface. explicitly defining relations permits their use in reasoning software and leads to a more flexible and powerful way of representing biomedical ontologies. Using the extended langua0067e and semantics avoids several mistakes commonly made in formalizing biomedical ontologies, and can be used to automatically detect inconsistencies. The use of our method enables the use of graph-based ontologies in OWL, and makes complex OWL ontologies accessible in a graph-based form. Thereby, our method provides the means to gradually move the representation of biomedical ontologies into formal knowledge

  15. Relations as patterns: bridging the gap between OBO and OWL

    PubMed Central

    2010-01-01

    Background Most biomedical ontologies are represented in the OBO Flatfile Format, which is an easy-to-use graph-based ontology language. The semantics of the OBO Flatfile Format 1.2 enforces a strict predetermined interpretation of relationship statements between classes. It does not allow flexible specifications that provide better approximations of the intuitive understanding of the considered relations. If relations cannot be accurately expressed then ontologies built upon them may contain false assertions and hence lead to false inferences. Ontologies in the OBO Foundry must formalize the semantics of relations according to the OBO Relationship Ontology (RO). Therefore, being able to accurately express the intended meaning of relations is of crucial importance. Since the Web Ontology Language (OWL) is an expressive language with a formal semantics, it is suitable to de ne the meaning of relations accurately. Results We developed a method to provide definition patterns for relations between classes using OWL and describe a novel implementation of the RO based on this method. We implemented our extension in software that converts ontologies in the OBO Flatfile Format to OWL, and also provide a prototype to extract relational patterns from OWL ontologies using automated reasoning. The conversion software is freely available at http://bioonto.de/obo2owl, and can be accessed via a web interface. Conclusions Explicitly defining relations permits their use in reasoning software and leads to a more flexible and powerful way of representing biomedical ontologies. Using the extended langua0067e and semantics avoids several mistakes commonly made in formalizing biomedical ontologies, and can be used to automatically detect inconsistencies. The use of our method enables the use of graph-based ontologies in OWL, and makes complex OWL ontologies accessible in a graph-based form. Thereby, our method provides the means to gradually move the representation of biomedical

  16. Activated partial thromboplastin time of owl monkey (Aotus trivirgatus) plasma.

    PubMed

    Mrema, J E; Johnson, G S; Kelley, S T; Green, T J

    1984-06-01

    Owl monkey plasma samples produced short, reproducible activated partial thromboplastin times, similar to those obtained with samples from many other mammalian species. This was an apparent contradiction to an earlier report of long irreproducible activated partial thromboplastin times from owl monkey samples. The discrepant data could not be explained by differences in anticoagulants (citrate or oxalate), assay reagents (partial thromboplastin with either diatomaceous earth or ellagic acid), or activation incubation times (2, 5, or 10 minutes); nor could they be explained by differences in the monkeys' sex, age or previous experimental exposure to Plasmodium falciparum malaria.

  17. Thermal adaptiveness of plumage color in screech owls

    USGS Publications Warehouse

    Mosher, J.A.; Henny, C.J.

    1976-01-01

    We measured oxygen consumption rates of 8 Screech? Owls (4 red and 4 gray phase) at 4 environmental temperatures, -10?, -5?, 5?, and 15?C. These data demonstrated a significant difference in oxygen uptake between color phases at -10? and -5?C. This supports our hypothesis that red phase Screech Owls are restricted in their northern distribution by color-related metabolic differences from the gray phase birds. The problems of low red phase occurrence in the Gulf Coast states and their absence from the Western states remain to be studied.

  18. Ecotoxicological suitability of floodplain habitats in The Netherlands for the little owl (Athene noctua vidalli).

    PubMed

    Van den Brink, N W; Groen, N M; De Jonge, J; Bosveld, A T C

    2003-01-01

    This study describes the actual risks of exposure to contaminants, which little owls (Athene noctua vidalli) face in Dutch river floodplains. The results indicate that PCBs pose a risk: not only are levels in little owls from floodplains higher than levels found in little owls from a reference site but the PCB patterns in owls from the floodplains also indicate induction of hepatic cytochrome P450 enzymes by dioxin like compounds, possibly PCBs. Of the heavy metals, only cadmium is thought to pose a risk in certain conditions, for example, when little owls are feeding only on earthworms over a prolonged period of time. The results do not indicate any effects on the occurrence of prey items of the little owl like for instance earthworm, beetles and shrews. Hence, it is not expected that little owls will be affected by diminishing prey availability due to contamination.

  19. Aber-OWL: a framework for ontology-based data access in biology.

    PubMed

    Hoehndorf, Robert; Slater, Luke; Schofield, Paul N; Gkoutos, Georgios V

    2015-01-28

    Many ontologies have been developed in biology and these ontologies increasingly contain large volumes of formalized knowledge commonly expressed in the Web Ontology Language (OWL). Computational access to the knowledge contained within these ontologies relies on the use of automated reasoning. We have developed the Aber-OWL infrastructure that provides reasoning services for bio-ontologies. Aber-OWL consists of an ontology repository, a set of web services and web interfaces that enable ontology-based semantic access to biological data and literature. Aber-OWL is freely available at http://aber-owl.net . Aber-OWL provides a framework for automatically accessing information that is annotated with ontologies or contains terms used to label classes in ontologies. When using Aber-OWL, access to ontologies and data annotated with them is not merely based on class names or identifiers but rather on the knowledge the ontologies contain and the inferences that can be drawn from it.

  20. Effects of experimental removal of barred owls on population demography of northern spotted owls in Washington and Oregon—2016 progress report

    USGS Publications Warehouse

    Wiens, J. David; Dugger, Katie M.; Lewicki, Krista E.; Simon, David C.

    2017-04-13

    Evidence indicates that competition with invasive barred owls (Strix varia) is causing rapid declines in populations of northern spotted owls (S. occidentalis caurina), and that the long-term persistence of spotted owls may be in question without additional management intervention. A pilot study in California showed that removal of barred owls in combination with habitat conservation may be able to slow or even reverse population declines of spotted owls at local scales, but it remains unknown whether similar results can be obtained in areas with different forest conditions and a greater density of barred owls. In 2015, we implemented a before-after-control-impact (BACI) experimental design on three study areas in Oregon and Washington with at least 20 years of pre-treatment demographic data on spotted owls to determine if removal of barred owls can improve localized population trends of spotted owls. Here, we report on research accomplishments and preliminary results from the first 21 months (March 2015–December 2016) of the planned 5-year experiment.

  1. Effects of experimental removal of barred owls on population demography of northern spotted owls in Washington and Oregon—2015 progress report

    USGS Publications Warehouse

    Wiens, J. David; Dugger, Katie M.; Lewicki, Krista E.; Simon, David C.

    2016-03-14

    Evidence indicates that competition with newly established barred owls (Strix varia) is causing rapid declines in populations of northern spotted owls (Strix occidentalis caurina), and that the longterm persistence of spotted owls may be in question without additional management intervention. A pilot study in California showed that lethal removal of barred owls in combination with habitat conservation may be able to slow or even reverse population declines of spotted owls at local scales, but it remains unknown whether similar results can be obtained in larger areas with different forest conditions and where barred owls are more abundant. In 2015, we implemented a before-after-controlimpact (BACI) experimental design on two study areas in Oregon and Washington with at least 20 years of pre-treatment demographic data on spotted owls to determine if removal of barred owls can improve population trends of spatially associated spotted owls. Here we provide an overview of our research accomplishments and preliminary results in Oregon and Washington in 2015.

  2. Quantifying space use of breeders and floaters of a long-lived species using individual movement data.

    PubMed

    Penteriani, Vincenzo; del Mar Delgado, Maria; Campioni, Letizia

    2015-06-01

    To date, animal movement studies have mostly analysed the movement behaviours of individuals at specific times of their lives, but we lack detailed information on how individual movements may be affected by the various and different changes that individuals experience throughout their life (e.g. life history phases, experience, age). Here, we attempt to identify differences in home range and movement behaviour between two different statuses, disperser vs. breeder, of a long-lived species (the eagle owl Bubo bubo). Information on home range and movement behaviour between different stages of an individual life are crucial for species conservation and management, as well as for basic knowledge on space use and rhythm of activity. Does the transition from an exploratory stage to moving within more familiar surroundings call for changes in the movement behaviour? We observed notable differences during the two stages of the owls' lives, with individuals having different home range behaviours and rhythms of activity depending on their social status. Significant differences in home range behaviour between the sexes began only with the acquisition of a breeding site. Breeders showed larger home ranges than dispersing individuals, although nightly variation of home ranges size was higher for dispersers than for breeders. Finally, dispersers were active throughout the night, whereas breeders displayed a less active movement phase at both the beginning and end of the night. Our results demonstrate it is important to consider individual variations in space use and movement behaviour due to the different life history phases that they attain during their lifetime. The knowledge of the different needs of a species across life stages may represent an important tool for species conservation because each phase of an individual life may need different requirements.

  3. Mesopredator release by an emergent superpredator: a natural experiment of predation in a three level guild.

    PubMed

    Chakarov, Nayden; Krüger, Oliver

    2010-12-06

    Intraguild predation (IGP) is widespread but it is often neglected that guilds commonly include many layers of dominance within. This could obscure the effects of IGP making unclear whether the intermediate or the bottom mesopredator will bear higher costs from the emergence of a new top predator. In one of the most extensive datasets of avian IGP, we analyse the impact of recolonization of a superpredator, the eagle owl Bubo bubo on breeding success, territorial dynamics and population densities of two mesopredators, the northern goshawk Accipiter gentilis and its IG prey, the common buzzard Buteo buteo. The data covers more than two decades and encompass three adjacent plots. Eagle owls only recolonized the central plot during the second decade, thereby providing a natural experiment. Both species showed a decrease in standardized reproductive success and an increase in brood failure within 1.5 km of the superpredator. During the second decade, territory dynamics of goshawks was significantly higher in the central plot compared to both other plots. No such pattern existed in buzzards. Goshawk density in the second decade decreased in the central plot, while it increased in both other plots. Buzzard density in the second decade rapidly increased in the north, remained unchanged in the south and increased moderately in the center in a probable case of mesopredator release. Our study finds support for top-down control on the intermediate mesopredator and both top-down and bottom-up control of the bottom mesopredator. In the face of considerable costs of IGP, both species probably compete to breed in predator-free refugia, which get mostly occupied by the dominant raptor. Therefore for mesopredators the outcome of IGP might depend directly on the number of dominance levels which supersede them.

  4. Quantifying space use of breeders and floaters of a long-lived species using individual movement data

    NASA Astrophysics Data System (ADS)

    Penteriani, Vincenzo; del Mar Delgado, Maria; Campioni, Letizia

    2015-06-01

    To date, animal movement studies have mostly analysed the movement behaviours of individuals at specific times of their lives, but we lack detailed information on how individual movements may be affected by the various and different changes that individuals experience throughout their life (e.g. life history phases, experience, age). Here, we attempt to identify differences in home range and movement behaviour between two different statuses, disperser vs. breeder, of a long-lived species (the eagle owl Bubo bubo). Information on home range and movement behaviour between different stages of an individual life are crucial for species conservation and management, as well as for basic knowledge on space use and rhythm of activity. Does the transition from an exploratory stage to moving within more familiar surroundings call for changes in the movement behaviour? We observed notable differences during the two stages of the owls' lives, with individuals having different home range behaviours and rhythms of activity depending on their social status. Significant differences in home range behaviour between the sexes began only with the acquisition of a breeding site. Breeders showed larger home ranges than dispersing individuals, although nightly variation of home ranges size was higher for dispersers than for breeders. Finally, dispersers were active throughout the night, whereas breeders displayed a less active movement phase at both the beginning and end of the night. Our results demonstrate it is important to consider individual variations in space use and movement behaviour due to the different life history phases that they attain during their lifetime. The knowledge of the different needs of a species across life stages may represent an important tool for species conservation because each phase of an individual life may need different requirements.

  5. Spontaneous otoacoustic emissions in the barn owl.

    PubMed

    Taschenberger, G; Manley, G A

    1997-08-01

    Spontaneous otoacoustic emissions (SOAE) were studied in a bird, the barn owl. They were found in 79% of the ears investigated, and each emitting ear generated on average 1.9 emissions. Their peak sound-pressure levels lay between -5.8 and 10.3 dB, and their centre frequencies between 2.3 and 10.5 kHz. The SOAE originated primarily in the upper quarter of the animal's hearing range, and derived from a specialized area previously described as being within an auditory fovea. Indeed, 93% of the emissions had centre frequencies above 7.5 kHz. The median of the frequency distances between neighbouring SOAE was 406 Hz (0.058 oct). The 3 dB bandwidth of the emissions depended on their amplitude above the noise: for SOAE whose level exceeded 10 dB above the noise floor, the 3 dB bandwidths ranged between 4.5 and 11.4 Hz. SOAE frequencies were temperature sensitive. Raising the temperature shifted the emissions to higher frequencies, and vice versa (the frequency shifted on average 0.039 oct/degrees C). External tones could suppress the level of SOAE, an effect that was highly tuned. For SOAE with frequencies between 2.5 and 10.5 kHz, the Q(10dB) values of 2 dB iso-suppression tuning curves (STC) varied from 1.07 to 10.40. The best thresholds of 2 dB STC were generally below 15 dB SPL.

  6. First observed instance of polygyny in Flammulated Owls

    Treesearch

    Brian D. Linkhart; Erin M. Evers; Julie D. Megler; Eric C. Palm; Catherine M. Salipante; Scott W. Yanco

    2008-01-01

    We document the first observed instance of polygyny in Flammulated Owls (Otus flammeolus) and the first among insectivorous raptors. Chronologies of the male's two nests, which were 510 m apart, were separated by nearly 2 weeks. Each brood initially consisted of three owlets, similar to the mean brood size in monogamous pairs. The male delivered...

  7. The California spotted owl: current state of knowledge

    Treesearch

    R.J. Gutiérrez; Patricia N. Manley; Peter A. Stine

    2017-01-01

    This conservation assessment represents a comprehensive review by scientists of the current scientific knowledge about the ecology, habitat use, population dynamics, and current threats to the viability of the California spotted owl (Strix occidentalis). It is based primarily on peer-reviewed published information with an emphasis on new scientific...

  8. The spotted owl in southern and central coastal California

    Treesearch

    R.J. Gutiérrez; Douglas J. Tempel; M. Zachariah Peery

    2017-01-01

    Spotted owl populations found in southern and central coastal California have received much less attention than those inhabiting the Sierra Nevada because of economic (effect of habitat conservation measures on timber harvest) and social issues (community stability and desire for naturally functioning ecosystems). Yet there has been continued concern over the...

  9. Chapter 4. Review of technical knowledge: Flammulated owls

    Treesearch

    D. Archibald McCallum

    1994-01-01

    The flammulated owl (Otus flammeolus) is a tiny, common predator on invertebrates that nests in cavities in western North American coniferous forests. It was thought by early workers to be rare (Bendire 1892, Bent 1938), but more recent opinion is that it is common but secretive (Marshall 1967, Winter 1971, 1974, Richmond et al. 1980). The...

  10. Burrowing (Speotyto cunicularia) Owl survival in prairie Canada

    Treesearch

    Kort M. Clayton; Josef K. Schmutz

    1997-01-01

    We studied survival of the endangered Burrowing Owl (Speotyto cunicularia) using radio-telemetry in both Alberta and Saskatchewan. Adult females exhibited the highest mean survival (0.83) whereas adult male (0.46) and juvenile (0.48) rates were similar. Most mortality occurred during the post-fledging period when there was a peak of activity around...

  11. tOWL: a temporal Web Ontology Language.

    PubMed

    Milea, Viorel; Frasincar, Flavius; Kaymak, Uzay

    2012-02-01

    Through its interoperability and reasoning capabilities, the Semantic Web opens a realm of possibilities for developing intelligent systems on the Web. The Web Ontology Language (OWL) is the most expressive standard language for modeling ontologies, the cornerstone of the Semantic Web. However, up until now, no standard way of expressing time and time-dependent information in OWL has been provided. In this paper, we present a temporal extension of the very expressive fragment SHIN(D) of the OWL Description Logic language, resulting in the temporal OWL language. Through a layered approach, we introduce three extensions: 1) concrete domains, which allow the representation of restrictions using concrete domain binary predicates; 2) temporal representation , which introduces time points, relations between time points, intervals, and Allen's 13 interval relations into the language; and 3) timeslices/fluents, which implement a perdurantist view on individuals and allow for the representation of complex temporal aspects, such as process state transitions. We illustrate the expressiveness of the newly introduced language by using an example from the financial domain.

  12. Night Owl: Maryland's After-Hours Reference Service.

    ERIC Educational Resources Information Center

    Duke, Deborah C.

    1994-01-01

    Discusses "Night Owl," a Maryland public library's after hours telephone reference service. Issues include project start-up, user profiles, types of questions, volume, after hours reference accessibility, security, costs, service limits, publicity, staffing, and employee turnover. Similar services in other states are cited. (Contains six…

  13. Spotted owl roost and nest site selection in northwestern California

    Treesearch

    J.A. Blakesley; A.B. Franklin; R.J. Gutierrez

    1992-01-01

    We directly observed roost and nest site selection in a population of northern spotted owls (Strix occidentalis caurina) in northwestern California during 1985-89. Because of potential biases caused by use of radio telemetry in previous studies, we examined habitat use relative to habitat availability at a level not previously reported for spotted...

  14. Design of a Monitoring Program for Northern Spotted Owls

    Treesearch

    Jonathan Bart; Douglas S. Robson

    1995-01-01

    This paper discusses methods for estimating population trends of Northern Spotted Owls (Strix occidentalis caurina) based on point counts. Although the monitoring program will have five distinct components, attention here is restricted to one of these: roadside surveys of territorial birds. Analyses of Breeding Bird Survey data and computer...

  15. From optics to attention: visual perception in barn owls.

    PubMed

    Harmening, Wolf M; Wagner, Hermann

    2011-11-01

    Barn owls are nocturnal predators which have evolved specific sensory and morphological adaptations to a life in dim light. Here, some of the most fundamental properties of spatial vision in barn owls are reviewed. The eye with its tubular shape is rigidly integrated in the skull so that eye movements are very much restricted. The eyes are oriented frontally, allowing for a large binocular overlap. Accommodation, but not pupil dilation, is coupled between the two eyes. The retina is rod dominated and lacks a visible fovea. Retinal ganglion cells form a marked region of highest density that extends to a horizontally oriented visual streak. Behavioural visual acuity and contrast sensitivity are poor, although the optical quality of the ocular media is excellent. A low f-number allows high image quality at low light levels. Vernier acuity was found to be a hyperacute percept. Owls have global stereopsis with hyperacute stereo acuity thresholds. Neurons of the visual Wulst are sensitive to binocular disparities. Orientation based saliency was demonstrated in a visual-search experiment, and higher cognitive abilities were shown when the owl's were able to use illusory contours for object discrimination.

  16. The "Owl Trail"--A Sensory Awareness Rope Trail

    ERIC Educational Resources Information Center

    Kauffman, Robert B.

    1978-01-01

    Constructed and experienced by students engaged in an outdoor education class at East Stroudsburg State College in Pennsylvania, the "Owl Trail" is a self guided rope trail (600 yards in length) employing such devices as sensory corrals, bridges, and "go to" ropes (ropes attached to the main rope which provide side trip…

  17. Online Writing Labs (OWLs): A Taxonomy of Options and Issues.

    ERIC Educational Resources Information Center

    Harris, Muriel; Pemberton, Michael

    1995-01-01

    Offers an overview and schema for understanding frequently used network technologies available for Online Writing Labs (OWLs)--electronic mail, gopher, World Wide Web, newsgroups, synchronous chat systems, and automated file retrieval systems. Considers ways writing centers' choices among these technologies are impacted by user access, network…

  18. The foundational model of anatomy in OWL: Experience and perspectives

    PubMed Central

    Zhang, Songmao; Bodenreider, Olivier

    2007-01-01

    We present the method developed for migrating the Foundational Model of Anatomy (FMA) from its representation with frames in Protégé to its logical representation in OWL and our experience in reasoning with it. Despite the extensive use of metaclasses in Protégé, it proved possible to convert the FMA from Protégé into OWL DL, while capturing most of its original features. The conversion relies on a set of translation and enrichment rules implemented with flexible options. Unsurprisingly, reasoning with the FMA in OWL proved to be a real challenge, due to its sheer size and complexity, and raised significant inference problems in terms of time and memory requirements. However, various smaller versions have been successfully handled by Racer. Some inconsistencies were identified and several classes reclassified. The results obtained so far show the advantage of OWL DL over frames and, more generally, the usefulness of DLs reasoners for building and maintaining the large-scale biomedical ontologies of the future Semantic Web. PMID:18360535

  19. Chapter 13. Current management situation: Great gray owls

    Treesearch

    Jon Verner

    1994-01-01

    The breeding range of great gray owls (Strix nebulosa) in the United States includes portions of Alaska, mountains in the western United States including portions of the Cascades and Sierra Nevada ranges and the northern Rockies, and portions of Minnesota, Michigan, Wisconsin, and New York (see Chapter 14 and Map 3). The species is sometimes observed...

  20. Spatiotemporal frequency and speed tuning in the owl visual wulst.

    PubMed

    Pinto, Lucas; Baron, Jerome

    2009-10-01

    The avian visual wulst is hodologically equivalent to the mammalian primary visual cortex (V1). In contrast to most birds, owls have a massive visual wulst, which shares striking functional similarities with V1. To provide a better understanding of how motion is processed within this area, we used sinusoidal gratings to characterize the spatiotemporal frequency and speed tuning profiles of 131 neurones recorded from awake burrowing owls. Cells were found to be clearly tuned to both spatial and temporal frequencies, and in a way that is similar to what has been reported in the striate cortex of primates and carnivores. Our results also suggest the presence of spatial frequency tuning domains in the wulst. Speed tuning was assessed by several methods devised to measure the degree of dependence between spatial and temporal frequency tuning. Although many neurones were found to be independently tuned, a significant proportion of cells showed at least some degree of dependence, compatible with the idea that some kind of initial transformation towards an explicit representation of speed is being carried out by the owl wulst. Interestingly, under certain constraints, a higher incidence of spatial frequency-invariant speed tuned profiles was obtained by combining our experimentally measured responses using a recent cortical model of speed tuning. Overall, our findings reinforce the notion that, like V1, the owl wulst is an important initial stage for motion processing, a function that is usually attributed to areas of the tectofugal pathway in lateral-eyed birds.

  1. Diets of California spotted owls in the Sierra National Forest

    Treesearch

    Thomas E. Munton; Kenneth D. Johnson; George N. Steger; Gary P. Eberlein

    2002-01-01

    From May 1987 through October 1992 and from July through August 1998, we studied diets of California spotted owls (Strix occidentalis occidentalis). Regurgitated pellets were collected at roost and nest sites between 1,000 and 7,600 ft elevation in the Sierra National Forest and were examined for remnant bones, feathers, and insect exoskeletons....

  2. Corticosterone and Dispersal in Western Screech-Owls (Otus kennicottii)

    Treesearch

    James R. Belthoff; Alfred M., Jr. Dufty

    1997-01-01

    Belthoff and Dufty (in press) posed a model for dispersal in screech-owls and similar nonmigratory birds. The model is based on interactions among hormonal changes, body condition, and locomotor activity patterns. It predicts that corticosterone increases in blood plasma prior to dispersal under endogenous and exogenous influences, and this increase mediates the...

  3. Modeling critical habitat for Flammulated Owls (Otus flammeolus)

    Treesearch

    David A. Christie; Astrid M. van Woudenberg

    1997-01-01

    Multiple logistic regression analysis was used to produce a prediction model for Flammulated Owl (Otus flammeolus) breeding habitat within the Kamloops Forest Region in south-central British Columbia. Using the model equation, a pilot habitat prediction map was created within a Geographic Information System (GIS) environment that had a 75.7 percent...

  4. Methods and materials for capturing and monitoring flammulated owls

    Treesearch

    Richard T. Reynolds; Brian D. Linkhart

    1984-01-01

    Techniques for locating, capturing, and monitoring activities and movements of Flammulated Owls were developed during four years of study. Adults responded to imitated territorial song throughout the nesting season. Nests were found by noting vocalizations and behaviors associated with courtship-feeding and food transfers between the sexes. After fledging, broods were...

  5. The "Owl Trail"--A Sensory Awareness Rope Trail

    ERIC Educational Resources Information Center

    Kauffman, Robert B.

    1978-01-01

    Constructed and experienced by students engaged in an outdoor education class at East Stroudsburg State College in Pennsylvania, the "Owl Trail" is a self guided rope trail (600 yards in length) employing such devices as sensory corrals, bridges, and "go to" ropes (ropes attached to the main rope which provide side trip…

  6. Diet of western Burrowing Owls wintering in southern Texas

    USGS Publications Warehouse

    Littles, C.J.; Williford, D.; Skoruppa, M.K.; Woodin, M.C.; Hickman, G.C.

    2007-01-01

    Winter diets of the western Burrowing Owl (Athene cunicularia hypugaea) are little known. We determined the diet of western Burrowing Owls wintering in southern Texas by analyzing the contents of 182 pellets collected over four winters (1999-2000, 2001-2002, 2002-2003, and 2003-2004) in three habitat types (agricultural, mainland grassland, and barrier island). Remains of a total of 7476 prey items were recovered, 98% of which were arthropods. Gryllidae (crickets) formed the largest component (50%) of the prey, followed by lepidopteran larvae (13%), beetles (8%), spiders (7%), and earwigs (6%). Although vertebrates, primarily small mammals and birds, represented only 2% of prey items by number, they represented most (71%) of the biomass. Northern pygmy mice (Baiomys taylori) and fulvous harvest mice (Reithrodontomys fulveccens) were the two most frequently consumed vertebrate species. In all habitats, arthropods, especially orthopterans, were the primary prey item by number, whereas vertebrates, primarily small mammals, were the most important by biomass. Greater consumption of arthropods by Burrowing Owls in agricultural areas may be a factor contributing to owl use of these highly altered environments. ?? 2007 The Raptor Research Foundation, Inc.

  7. Online Writing Labs (OWLs): A Taxonomy of Options and Issues.

    ERIC Educational Resources Information Center

    Harris, Muriel; Pemberton, Michael

    1995-01-01

    Offers an overview and schema for understanding frequently used network technologies available for Online Writing Labs (OWLs)--electronic mail, gopher, World Wide Web, newsgroups, synchronous chat systems, and automated file retrieval systems. Considers ways writing centers' choices among these technologies are impacted by user access, network…

  8. Night Owl: Maryland's After-Hours Reference Service.

    ERIC Educational Resources Information Center

    Duke, Deborah C.

    1994-01-01

    Discusses "Night Owl," a Maryland public library's after hours telephone reference service. Issues include project start-up, user profiles, types of questions, volume, after hours reference accessibility, security, costs, service limits, publicity, staffing, and employee turnover. Similar services in other states are cited. (Contains six…

  9. Intra- and interspecific calling in a Tropical Owl Community

    Treesearch

    Paula L. Enriquez; J. Luis Rangel Salazar

    1997-01-01

    We studied the intra- and interspecific responses to playback of pre-recorded calls by five tropical humid forest owl species at La Selva preserve in northeastern Costa Rica from April to September 1995. Response to conspecific broadcast calls differed among species (X² = 24.4; df = 1; P Otus guatemalae...

  10. New perspectives on the owl's map of auditory space

    PubMed Central

    Pena, Jose L.; Gutfreund, Yoram

    2013-01-01

    A map of sound direction was found in the owl's midbrain more than three decades ago. This finding suggested that the brain reconstructs spatial coordinates to represent them. Subsequent research elucidated the variables used to compute the map. Here we provide a review of the processes leading to its emergence and an updated perspective on how and what information is represented. PMID:24492079

  11. Owls see in stereo much like humans do.

    PubMed

    van der Willigen, Robert F

    2011-06-10

    While 3D experiences through binocular disparity sensitivity have acquired special status in the understanding of human stereo vision, much remains to be learned about how binocularity is put to use in animals. The owl provides an exceptional model to study stereo vision as it displays one of the highest degrees of binocular specialization throughout the animal kingdom. In a series of six behavioral experiments, equivalent to hallmark human psychophysical studies, I compiled an extensive body of stereo performance data from two trained owls. Computer-generated, binocular random-dot patterns were used to ensure pure stereo performance measurements. In all cases, I found that owls perform much like humans do, viz.: (1) disparity alone can evoke figure-ground segmentation; (2) selective use of "relative" rather than "absolute" disparity; (3) hyperacute sensitivity; (4) disparity processing allows for the avoidance of monocular feature detection prior to object recognition; (5) large binocular disparities are not tolerated; (6) disparity guides the perceptual organization of 2D shape. The robustness and very nature of these binocular disparity-based perceptual phenomena bear out that owls, like humans, exploit the third dimension to facilitate early figure-ground segmentation of tangible objects.

  12. California spotted owl: scientific considerations for forest planning

    Treesearch

    John J. Keane

    2014-01-01

    California spotted owls (Strix occidentalis occidentalis) (fig. 1) have been at the forefront of Sierra Nevada management and conservation debates for 25 years because of their strong habitat associations with commercially valuable large trees, snags, and late-successional forests. Initial concerns focused on the effects of timber harvest on large...

  13. Introgression and dispersal among spotted owl (Strix occidentatlis) subspecies.

    Treesearch

    W.Chris Funk; Eric D. Forsman; Thomas D. Mullins; Susan M. Haig

    2008-01-01

    Population genetics plays an increasingly important role in the conservation and management of declining species, particularly for defining taxonomic units. Subspecies are recognized by several conservation organizations and countries and receive legal protection under the US Endangered Species Act (ESA). Two subspecies of spotted owls, northern (Strix...

  14. Modeling seasonal detection patterns for burrowing owl surveys

    Treesearch

    Quresh S. Latif; Kathleen D. Fleming; Cameron Barrows; John T. Rotenberry

    2012-01-01

    To guide monitoring of burrowing owls (Athene cunicularia) in the Coachella Valley, California, USA, we analyzed survey-method-specific seasonal variation in detectability. Point-based call-broadcast surveys yielded high early season detectability that then declined through time, whereas detectability on driving surveys increased through the season. Point surveys...

  15. How barn owls (Tyto alba) visually follow moving voles (Microtus socialis) before attacking them.

    PubMed

    Fux, Michal; Eilam, David

    2009-09-07

    The present study focused on the movements that owls perform before they swoop down on their prey. The working hypothesis was that owl head movements reflect the capacity to efficiently follow visually and auditory a moving prey. To test this hypothesis, five tame barn owls (Tyto alba) were each exposed 10 times to a live vole in a laboratory setting that enabled us to simultaneously record the behavior of both owl and vole. Bi-dimensional analysis of the horizontal and vertical projections of movements revealed that owl head movements increased in amplitude parallel to the vole's direction of movement (sideways or away from/toward the owl). However, the owls also performed relatively large repetitive horizontal head movements when the voles were progressing in any direction, suggesting that these movements were critical for the owl to accurately locate the prey, independent of prey behavior. From the pattern of head movements we conclude that owls orient toward the prospective clash point, and then return to the target itself (the vole) - a pattern that fits an interception rather than a tracking mode of following a moving target. The large horizontal component of head movement in following live prey may indicate that barn owls either have a horizontally narrow fovea or that these movements serve in forming a motion parallax along with preserving image acuity on a horizontally wide fovea.

  16. Comparative study of visual pathways in owls (Aves: Strigiformes).

    PubMed

    Gutiérrez-Ibáñez, Cristián; Iwaniuk, Andrew N; Lisney, Thomas J; Wylie, Douglas R

    2013-01-01

    Although they are usually regarded as nocturnal, owls exhibit a wide range of activity patterns, from strictly nocturnal, to crepuscular or cathemeral, to diurnal. Several studies have shown that these differences in the activity pattern are reflected in differences in eye morphology and retinal organization. Despite the evidence that differences in activity pattern among owl species are reflected in the peripheral visual system, there has been no attempt to correlate these differences with changes in the visual regions in the brain. In this study, we compare the relative size of nuclei in the main visual pathways in nine species of owl that exhibit a wide range of activity patterns. We found marked differences in the relative size of all visual structures among the species studied, both in the tectofugal and the thalamofugal pathway, as well in other retinorecipient nuclei, including the nucleus lentiformis mesencephali, the nucleus of the basal optic root and the nucleus geniculatus lateralis, pars ventralis. We show that the barn owl (Tyto alba), a species widely used in the study of the integration of visual and auditory processing, has reduced visual pathways compared to strigid owls. Our results also suggest there could be a trade-off between the relative size of visual pathways and auditory pathways, similar to that reported in mammals. Finally, our results show that although there is no relationship between activity pattern and the relative size of either the tectofugal or the thalamofugal pathway, there is a positive correlation between the relative size of both visual pathways and the relative number of cells in the retinal ganglion layer. Copyright © 2012 S. Karger AG, Basel.

  17. Factors affecting detection of burrowing owl nests during standardized surveys

    USGS Publications Warehouse

    Conway, C.J.; Garcia, V.; Smith, M.D.; Hughes, K.

    2008-01-01

    Identifying causes of declines and evaluating effects of management practices on persistence of local populations of burrowing owls (Athene cunicularia) requires accurate estimates of abundance and population trends. Moreover, regulatory agencies in the United States and Canada typically require surveys to detect nest burrows prior to approving developments or other activities in areas that are potentially suitable for nesting burrowing owls. In general, guidelines on timing of surveys have been lacking and surveys have been conducted at different times of day and in different stages of the nesting cycle. We used logistic regression to evaluate 7 factors that could potentially affect probability of a surveyor detecting a burrowing owl nest. We conducted 1,444 detection trials at 323 burrowing owl nests within 3 study areas in Washington and Wyoming, USA, between February and August 2000-2002. Detection probability was highest during the nestling period and increased with ambient temperature. The other 5 factors that we examined (i.e., study area, time of day, timing within the breeding season, wind speed, % cloud cover) interacted with another factor to influence detection probability. Use of call-broadcast surveys increased detection probability, even during daylight hours when we detected >95% of owls visually. Optimal timing of surveys will vary due to differences in breeding phenology and differences in nesting behavior across populations. Nevertheless, we recommend ???3 surveys per year: one that coincides with the laying and incubation period, another that coincides with the early nestling period, and a third that coincides with the late nestling period. In northern latitudes, surveys can be conducted throughout the day.

  18. Population dynamics of spotted owls in the Sierra Nevada, California

    USGS Publications Warehouse

    Blakesley, J.A.; Seamans, M.E.; Conner, M.M.; Franklin, A.B.; White, Gary C.; Gutierrez, R.J.; Hines, J.E.; Nichols, J.D.; Munton, T.E.; Shaw, D.W.H.; Keane, J.J.; Steger, G.N.; McDonald, T.L.

    2010-01-01

    The California spotted owl (Strix occidentalis occidentalis) is the only spotted owl subspecies not listed as threatened or endangered under the United States Endangered Species Act despite petitions to list it as threatened. We conducted a meta-analysis of population data for 4 populations in the southern Cascades and Sierra Nevada, California, USA, from 1990 to 2005 to assist a listing evaluation by the United States Fish and Wildlife Service. Our study areas (from N to S) were on the Lassen National Forest (LAS), Eldorado National Forest (ELD), Sierra National Forest (SIE), and Sequoia and Kings Canyon National Parks (SKC). These study areas represented a broad spectrum of habitat and management conditions in these mountain ranges. We estimated apparent survival probability, reproductive output, and rate of population change for spotted owls on individual study areas and for all study areas combined (meta-analysis) using model selection or model-averaging based on maximum-likelihood estimation. We followed a formal protocol to conduct this analysis that was similar to other spotted owl meta-analyses. Consistency of field and analytical methods among our studies reduced confounding methodological effects when evaluating results. We used 991 marked spotted owls in the analysis of apparent survival. Apparent survival probability was higher for adult than for subadult owls. There was little difference in apparent survival between male and female owls. Model-averaged mean estimates of apparent survival probability of adult owls varied from 0.811 ?? 0.021 for females at LAS to 0.890 ?? 0.016 for males at SKC. Apparent survival increased over time for owls of all age classes at LAS and SIE, for adults at ELD, and for second-year subadults and adults at SKC. The meta-analysis of apparent survival, which included only adult owls, confirmed an increasing trend in survival over time. Survival rates were higher for owls on SKC than on the other study areas. We analyzed data

  19. Barn Owl (Tyto alba) and Long-Eared Owl (Asio otus) mortality along motorways in Bourgogne-Champagne: report and suggestions

    Treesearch

    Hugues Baudvin

    1997-01-01

    The purpose of the study was to find where and why two species of owls were killed by traffic along motorways. Three different factors have an important influence on the mortality of the two owl species: the biotops crossed by motorways, the road elevation and the presence of small rodents, the Common Vole (Microtus arvalis) being most numerous. In...

  20. The influence of broadcast tape-recorded calls on captures of fall migrant Northern Saw-whet Owls (Aegolius acadicus) and Long-eared Owls (Asio otus)

    Treesearch

    David L. Evans

    1997-01-01

    Nocturnal netting operations have been conducted at the Hawk Ridge Nature Reserve since 1972. From 1988 to 1992 a recording of human whistles simulating the calls of fall migrant Northern Saw-whet Owls (Aegolius acadicus) was broadcast on a random, on or off, half-night basis. Mist net captures of Saw-whet Owls increased about fourfold during the...

  1. The Dusk Chorus from an Owl Perspective: Eagle Owls Vocalize When Their White Throat Badge Contrasts Most

    PubMed Central

    Penteriani, Vincenzo; Delgado, Maria del Mar

    2009-01-01

    Background An impressive number of studies have investigated bird vocal displays, and many of them have tried to explain the widespread phenomenon of the so-called dawn and dusk chorus, the sunrise and sunset peaks in bird song output. As many as twelve non-exclusive hypotheses have been proposed to explain why twilight peaks in vocal display might be advantageous; but, even after more than two decades of study, the basis underlying the dusk and dawn chorus is still unclear. Moreover, to date, the majority of studies on this topic have focused on songbirds. Methodology/Principal Findings We investigate here a novel hypothesis on why nocturnal birds with patches of white feathers call at twilight. We propose that white plumage patches and the timing of visual signaling have co-evolved to maximize the effectiveness of social communication such as the dusk chorus. This hypothesis centers on the recent discovery that eagle owls can adopt specific forms of visual signaling and is supported by the observation that adult eagle owls possess a white throat badge that is only visible during vocal displays. By monitoring the calling of eagle owls at dusk, a peak time for bird call output, we found that white throat badges contrasted most with the surrounding background during the owls' twilight chorusing. Conclusions/Significance Crepuscular and nocturnal species appear to have evolved white patches that, shown in association with vocal displays, allow them to communicate in dark surroundings. The evolution of a white badge that operates jointly with call displays at dawn and dusk may be relevant to the eagle owls' social dynamics. Our explanation for the dusk chorus may possibly represent an overlooked but common pattern of signaling among crepuscular and nocturnal birds that combine patches of white feathers with twilight displays. Furthermore, our findings could be relevant to songbirds that breed in dark forest habitats and have contrasting white badges, as well as birds

  2. A Process for the Representation of openEHR ADL Archetypes in OWL Ontologies.

    PubMed

    Porn, Alex Mateus; Peres, Leticia Mara; Didonet Del Fabro, Marcos

    2015-01-01

    ADL is a formal language to express archetypes, independent of standards or domain. However, its specification is not precise enough in relation to the specialization and semantic of archetypes, presenting difficulties in implementation and a few available tools. Archetypes may be implemented using other languages such as XML or OWL, increasing integration with Semantic Web tools. Exchanging and transforming data can be better implemented with semantics oriented models, for example using OWL which is a language to define and instantiate Web ontologies defined by W3C. OWL permits defining significant, detailed, precise and consistent distinctions among classes, properties and relations by the user, ensuring the consistency of knowledge than using ADL techniques. This paper presents a process of an openEHR ADL archetypes representation in OWL ontologies. This process consists of ADL archetypes conversion in OWL ontologies and validation of OWL resultant ontologies using the mutation test.

  3. [Brant goose colonies near snowy owls: internest distances in relation to lemming and arctic fox abundance].

    PubMed

    Kharitonov, S P; Volkov, A E; Willems, F; van Kleef, H; Klaassen, R H G; Nowak, D J; Nowak, A I; Bublichenko, A G

    2008-01-01

    Brant goose colonies around snowy owl nests have been studied near Meduza Bay (73 degrees 21' N, 80 degrees 32' E) and in the lower reaches of the Uboinaya River (73 degrees 37' N, 82 degrees 10' E), the northwestern Taimyr Peninsula, from 1999 to 2006. All brant nests within 680 m from an owl nest have been regarded as an individual colony. The results show that the area of the colony is always larger than the guarded area around the owl nest. In years of high abundance of lemmings, brant geese nest generally closer to the owl nest than in years of high abundance. When arctic foxes are abundant, however, brant geese nest significantly closer to owls than when the foxes are scarce, irrespective of lemming abundance. The mechanism of brant colony formation around owl nests is based on a number of stimuli.

  4. Burrowing owl nesting productivity: A comparison between artificial and natural burrows on and off golf courses

    USGS Publications Warehouse

    Smith, M.D.; Conway, C.J.; Ellis, L.A.

    2005-01-01

    Burrowing owl (Athene cunicularia) populations are declining in many portions of their range, and lack of suitable nesting burrows is thought to be one reason for observed declines. Burrowing owls are attracted to golf courses because the birds generally nest and forage in short-grass, open areas, yet golf courses seldom have suitable nesting burrows. We examined the efficacy of installing artificial nesting burrows on golf courses as a way to help restore local burrowing owl populations. From 2001-2004 we monitored over 175 natural burrows off golf courses, 14 natural burrows on golf courses, 86 artificial burrows off golf courses, and 130 artificial burrows on golf courses. Owls located and used 8 of the 130 artificial burrows installed on golf courses (4 were used as nests). Owls selected burrows that were closer to existing natural burrows, farther from maintained areas (areas receiving turf maintenance by golf course staff), and farther from sprinkler heads. All 4 of the artificial burrows used as nests successfully fledged young, and annual site fidelity for owls nesting on golf courses was higher than for owls nesting off golf courses. However, annual fecundity of owls nesting on golf courses was lower than that of owls nesting off golf courses. If golf courses have sufficiently large nonmaintained areas and there are nesting owls nearby, course managers potentially can help in restoring local burrowing owl populations by installing artificial nesting burrows on the periphery of the course. However, the low fecundity on golf courses reported here should be more thoroughly examined before artificial burrows are used to attract owls to golf courses.

  5. Ultrasonographic monitoring of a spontaneous abortion in an owl monkey (Aotus nancymaae).

    PubMed

    Schuler, A Michele; Parks, Virginia L; Abee, Christian R; Scammell, Jonathan G

    2007-07-01

    This case report describes the ultrasonographic findings during an idiopathic spontaneous abortion in an owl monkey. The female owl monkey presented for a transabdominal ultrasonogram to evaluate her pregnancy. This evaluation is a routine monitoring procedure in our owl monkey breeding colony. Although the fetus and placenta appeared normal at the initial scan, no fetal heartbeat could be detected. We followed the abortion with serial ultrasonographic scans and documented complete involution of the uterus post-abortion.

  6. Detecting West Nile Virus in Owls and Raptors by an Antigen-capture Assay

    PubMed Central

    Campbell, Douglas G.; Barker, Ian K.; Lindsay, Robbin; Hunter, Bruce

    2004-01-01

    We evaluated a rapid antigen-capture assay (VecTest) for detection of West Nile virus in oropharyngeal and cloacal swabs, collected at necropsy from owls (N = 93) and raptors (N = 27). Sensitivity was 93.5%–95.2% for northern owl species but <42.9% for all other species. Specificity was 100% for owls and 85.7% for raptors. PMID:15663862

  7. Home range characteristics of Mexican Spotted Owls in the Rincon Mountains, Arizona

    USGS Publications Warehouse

    Willey, David W.; Van Riper, Charpes III

    2014-01-01

    We studied a small isolated population of Mexican Spotted Owls (Strix occidentalis lucida) from 1996–1997 in the Rincon Mountains of Saguaro National Park, southeastern Arizona, USA. All mixed-conifer and pine-oak forest patches in the park were surveyed for Spotted Owls, and we located, captured, and radio-tagged 10 adult birds representing five mated pairs. Using radio-telemetry, we examined owl home range characteristics, roost habitat, and monitored reproduction within these five territories. Breeding season (Mar–Sep) home range size for 10 adult owls (95% adaptive kernel isopleths) averaged 267 ha (±207 SD), and varied widely among owls (range 34–652 ha). Mean home range size for owl pairs was 478 ha (±417 ha SD), and ranged from 70–1,160 ha. Owls that produced young used smaller home ranges than owls that had no young. Six habitat variables differed significantly between roost and random sites, including: percent canopy cover, number of trees, number of vegetation layers, average height of trees, average diameter of trees, and tree basal area. Radio-marked owls remained in their territories following small prescribed management fires within those territories, exhibiting no proximate effects to the presence of prescribed fire.

  8. Two Types of Alpha Satellite DNA in Distinct Chromosomal Locations in Azara's Owl Monkey

    PubMed Central

    Prakhongcheep, Ornjira; Hirai, Yuriko; Hara, Toru; Srikulnath, Kornsorn; Hirai, Hirohisa; Koga, Akihiko

    2013-01-01

    Alpha satellite DNA is a repetitive sequence known to be a major DNA component of centromeres in primates (order Primates). New World monkeys form one major taxon (parvorder Platyrrhini) of primates, and their alpha satellite DNA is known to comprise repeat units of around 340 bp. In one species (Azara's owl monkey Aotus azarae) of this taxon, we identified two types of alpha satellite DNA consisting of 185- and 344-bp repeat units that we designated as OwlAlp1 and OwlAlp2, respectively. OwlAlp2 exhibits similarity throughout its entire sequence to the alpha satellite DNA of other New World monkeys. The chromosomal locations of the two types of sequence are markedly distinct: OwlAlp1 was observed at the centromeric constrictions, whereas OwlAlp2 was found in the pericentric regions. From these results, we inferred that OwlAlp1 was derived from OwlAlp2 and rapidly replaced OwlAlp2 as the principal alpha satellite DNA on a short time scale at the speciation level. A less likely alternative explanation is also discussed. PMID:23477842

  9. Multiscale habitat selection by burrowing owls in black-tailed prairie dog colonies

    USGS Publications Warehouse

    Lantz, S.J.; Conway, C.J.; Anderson, S.H.

    2007-01-01

    Some populations of western burrowing owls (Athene cunicularia hypugaea) have declined in recent decades. To design and implement effective recovery efforts, we need a better understanding of how distribution and demographic traits are influenced by habitat quality. To this end, we measured spatial patterns of burrowing owl breeding habitat selection within black-tailed prairie dog (Cynomys ludovicianus) colonies in northeastern Wyoming, USA. We compared burrow-, site-, colony-, and landscape-scale habitat parameters between burrowing owl nest burrows (n = 105) and unoccupied burrows (n = 85). We sampled 4 types of prairie dog colonies: 1) owl-occupied, active with prairie dogs (n = 16); 2) owl-occupied, inactive (n = 13); 3) owl-unoccupied, active (n = 14); and 4) owl-unoccupied, inactive (n = 14). We used an information-theoretic approach to examine a set of candidate models of burrowing owl nest-site selection. The model with the most support included variables at all 4 spatial scales, and results were consistent among the 4 types of prairie dog colonies. Nest burrows had longer tunnels, more available burrows within 30 m, and less shrub cover within 30 m, more prairie dog activity within 100 m, and were closer to water than unoccupied burrows. The model correctly classified 76% of cases, all model coefficients were stable, and the model had high predictive ability. Based on our results, we recommend actions to ensure persistence of the remaining prairie dog colonies as an important management strategy for burrowing owl conservation in the Great Plains of North America.

  10. Two types of alpha satellite DNA in distinct chromosomal locations in Azara's owl monkey.

    PubMed

    Prakhongcheep, Ornjira; Hirai, Yuriko; Hara, Toru; Srikulnath, Kornsorn; Hirai, Hirohisa; Koga, Akihiko

    2013-06-01

    Alpha satellite DNA is a repetitive sequence known to be a major DNA component of centromeres in primates (order Primates). New World monkeys form one major taxon (parvorder Platyrrhini) of primates, and their alpha satellite DNA is known to comprise repeat units of around 340 bp. In one species (Azara's owl monkey Aotus azarae) of this taxon, we identified two types of alpha satellite DNA consisting of 185- and 344-bp repeat units that we designated as OwlAlp1 and OwlAlp2, respectively. OwlAlp2 exhibits similarity throughout its entire sequence to the alpha satellite DNA of other New World monkeys. The chromosomal locations of the two types of sequence are markedly distinct: OwlAlp1 was observed at the centromeric constrictions, whereas OwlAlp2 was found in the pericentric regions. From these results, we inferred that OwlAlp1 was derived from OwlAlp2 and rapidly replaced OwlAlp2 as the principal alpha satellite DNA on a short time scale at the speciation level. A less likely alternative explanation is also discussed.

  11. Density and habitat associations of Barred Owls at the edge of their range in Oklahoma

    USGS Publications Warehouse

    Winton, Brian R.; Leslie, David M.

    2004-01-01

    We assessed breeding-pair density and habitat associations of Barred Owls (Strix varia) at the edge of their range in north-central Oklahoma in 1995-1996. We played taped calls of Barred Owls to solicit and record responses (visual and auditory) and thereby determine density in our 1155-ha study area. Numbers of owls ranged from 7 pairs in 1995 to 11 pairs in 1996, or 1 Barred Owl pair/105-165 ha in a relatively contiguous bottomland forest. To assess habitat associations, we overlaid core areas of owl activity, as inferred from the locations of Barred Owl responses, on aerial photographs and quantified habitats in a 0.65-km2 cell surrounding owl core areas. Barred owl pairs were associated with closed-canopy forest (62.8%), fallow agricultural fields (10.6%), water (8.1%), and treeless (open) areas (6.2%), which differed from single owls (presumed nonbreeders) that showed a greater affinity for open-canopy forest and agricultural fields.

  12. Avian trichomonosis in spotted owls (Strix occidentalis): Indication of opportunistic spillover from prey.

    PubMed

    Rogers, Krysta H; Girard, Yvette A; Woods, Leslie; Johnson, Christine K

    2016-12-01

    Avian trichomonosis, caused by the flagellated protozoan parasite Trichomonas gallinae, has variable pathogenicity among bird species ranging from asymptomatic infections to severe disease periodically manifesting in epidemic mortality. Traditionally, columbids are identified as highly susceptible to infection with occasional spillover into raptors that prey on infected birds. We identified avian trichomonosis in two dead California spotted owls (Strix occidentalis occidentalis) and three dead northern spotted owls (S. o. caurina) in California during 2011-2015; infection was confirmed in four owls by PCR. Pathologic lesions associated with trichomonosis in the owls included caseonecrotic lesions of the upper palate accompanied by oropharyngitis, cellulitis, myositis, and/or sinusitis. Spotted owls are known to mainly feed on small mammals; therefore, the source of infection as well as the significance of the disease in spotted owls is unclear. These owl trichomonosis cases coincided temporally and spatially with three trichomonosis epidemics in band-tailed pigeons (Patagioenas fasciata monilis). The same parasite, T. gallinae subtype A2, was isolated from the spotted owls and band-tailed pigeons, suggesting the owls became infected when opportunistically feeding on pigeons during mortality events. Avian trichomonosis is an important factor in the decline of the Pacific Coast band-tailed pigeon population with near-annual mortality events during the last 10 years and could have conservation implications for raptor species at risk, particularly those that are facing multiple threats.

  13. Acoustic surveys for Mexican spotted owls (Strix occidentalis lucida): An analysis

    NASA Astrophysics Data System (ADS)

    Bowles, Ann E.; Martindell, Chris; Plotkin, Kenneth J.; Ikelheimer, Bruce; Lavallee, Tim

    2002-05-01

    During acoustic surveys for Mexican spotted owls, the effective detection range is presumed to be 0.25 mi (433 m). However, variations within and between surveys are observed, leading to a variance in owl density estimates. While owl behavior may explain some variation, topography and ambient noise are also likely to be important. To determine the influence of these factors, data from acoustic surveys for Mexican spotted owls in the Gila National Forest (April-July, 2000-2001) were examined. Measurements of owl and human call levels were made with a Sony TCD-10 Pro II DAT equipped with an ACO 7013 microphone. Ambient noise was collected using 40 Larson-Davis 820 and 824 sound level meters in owl activity centers. Wyle Laboratories NMSIM software was used to model propagation of owl and human calls. Owls produced calls with estimated maximum source levels of 92-98-dB SPL. Human callers produced maximum source levels of 88-95-dB SPL. Detection was possible out to more than 2 km under ideal conditions, but topography and ambient noise had a large effect. Corrections for these factors would greatly improve estimates of area surveyed, and thus owl density estimates. [Work supported by the U.S. Air Force, Air Combat Command.

  14. The electroretinogram of the little owl (Athene noctua).

    PubMed

    Porciatti, V; Fontanesi, G; Bagnoli, P

    1989-01-01

    Electroretinographic responses (ERGs) have been recorded from the cornea of the little owl (Athene noctua) in response to single light flashes and to alternating sinusoidal gratings (pattern) at different levels of light adaptation. Both flash- and pattern-evoked ERGs show scotopic as well as photopic components. The pattern evoked ERG is spatially tuned with tuning functions which shift towards lower frequencies by reducing the mean luminance. The retinal acuity is about 6 c/deg at 2.3 log cd/m2 and decreases progressively by reducing the mean luminance. No pattern ERG can be recorded beyond -6.7 log cd/m2 at any spatial frequency. The pattern ERG amplitude decreases progressively by reducing the contrast. The extrapolated contrast threshold is about 1%. Acuity and contrast sensitivity ERG values are in the range of those obtained by operant techniques in other species with duplex retinae such as owls and cats.

  15. Nanoscale Bio-Molecular Control Using EC-OWLS

    SciTech Connect

    Bearinger, J P; Voros, J; Hubbell, J A; Textor, M

    2002-11-20

    A recently developed technique termed ''Electrochemical Optical Waveguide Lightmode Spectroscopy'' (EC-OWLS) [1] combines evanescent-field optical sensing with electrochemical control of surface adsorption processes. Initial EC-OWLS investigations efficiently monitored molecular surface adsorption and layer thickness changes of an adsorbed polymer layer examined in situ as a function of potential applied to a waveguide1. A layer of indium tin oxide (ITO) served as both a high refractive index waveguide for optical sensing, and a conductive electrode; an electrochemical flow-through fluid cell incorporated working, reference and counter electrodes. Poly(L-lysine)-grafted-poly(ethylene glycol) (PLL-g-PEG) served as a model, polycation adsorbate. Results indicate that adsorption and desorption of PLL-g-PEG from aqueous buffer are a function of applied potential, and that binding events subsequent to PLL-g-PEG functionalization are dependent on reorganization in the molecular adlayer.

  16. Development of auditory sensitivity in the barn owl.

    PubMed

    Kraemer, Anna; Baxter, Caitlin; Hendrix, Alayna; Carr, Catherine E

    2017-07-08

    Adult barn owl hearing is acute, but development of this sense is not well understood. We, therefore, measured auditory brainstem responses in barn owls from before the onset of hearing (posthatch day 2, or P2) to adulthood (P69). The first consistent responses were detected at P4 for 1 and 2 kHz, followed by responses to 0.5 and 4 kHz at P9, and 5 kHz at P13. Sensitivity to higher frequencies increased with age, with responses to 12 kHz appearing about 2 months after hatching, once the facial ruff was mature. Therefore, these altricial birds achieve their sensitivity to sound during a prolonged period of development, which coincides with maturation of the skull and facial ruff (Haresign and Moiseff in Auk 105:699-705, 1988).

  17. Airborne ocean water lidar (OWL) real time processor (RTP)

    NASA Astrophysics Data System (ADS)

    Hryszko, M.

    1995-03-01

    The Hyperflo Real Time Processor (RTP) was developed by Pacific-Sierra Research Corporation as a part of the Naval Air Warfare Center's Ocean Water Lidar (OWL) system. The RTP was used for real time support of open ocean field tests at Barbers Point, Hawaii, in March 1993 (EMERALD I field test), and Jacksonville, Florida, in July 1994 (EMERALD I field test). This report describes the system configuration, and accomplishments associated with the preparation and execution of these exercises. This document is intended to supplement the overall test reports and provide insight into the development and use of the PTP. A secondary objective is to provide basic information on the capabilities, versatility and expandability of the Hyperflo RTP for possible future projects. It is assumed herein that the reader has knowledge of the OWL system, field test operations, general lidar processing methods, and basic computer architecture.

  18. Malaria in an eastern screech owl (Otus asio).

    PubMed

    Tavernier, Paul; Saggese, Miguel; Sagesse, Miguel; Van Wettere, Arnaud; Redig, Patrick

    2005-09-01

    Owls are frequent carriers of blood parasites but clinical malaria infections are rare. Various stages of Plasmodium subpraecox were seen in 90% of the erythrocytes of an Eastern screech owl (Otus asio) showing symptoms consistent with malaria 1 wk after admission for traumatic injuries. An additional unidentified blood parasite, either a Plasmodium or a Haemoproteus spp. was found in small numbers of red blood cells on blood films examined at admission and at day 7 postadmission. Combined infestation, trauma-induced stress, and iatrogenic corticosteroid administration are possible factors that could have induced disease. Oral treatment with mefloquine at 30 mg/kg, repeated after 12, 24, and 48 hr, proved successful in eliminating both organisms and signs of clinical disease.

  19. Reproductive success of screech owls fed Aroclor 1248

    USGS Publications Warehouse

    McLane, M.A.R.; Hughes, D.L.

    1980-01-01

    Aroclor? 1248 was fed to captive screech owls (Otus asio) at the rate of three ppm in the diet to determine if reproductive effects such as fewer eggs per clutch, lower hatchability, malformation of the chicks, or higher mortality rates of chicks would appear in this raptorial species as they did in chickens. There were no effects on eggshell thickness, number of eggs laid, young hatched, and young fledged from feeding a low level of Aroclor? 1248 to captive screech owls. The polychlorinated biphenyl (PCB) residues found in the eggs of the dosed birds ranged from 3.9 ppm to 17.8 ppm. Background PCB residues in the diet of all experimental birds ranged from non-detected to 0.62 ppm.

  20. Miniature Optical Wide-Angle-Lens Startracker (Mini-OWLS)

    NASA Astrophysics Data System (ADS)

    Miller, Rick; Coulter, Joe E.; Levine, Seymour

    1993-02-01

    This paper provides a brief overview of the design considerations and the current status of the Miniature Optical Wide-Angle Lens Startracker Program. Mini-OWLS offers a revolutionary alternative to the conventional startracker. It is a small, lightweight, low cost, high performance startracker that can be used in a variety of applications including calibration and alignment of Inertial Measurement Units (IMU's) Mini-OWLS makes use of a strap down design incorporating Holographic Optical Elements (HOES) in place of conventional optics. HOES can be multiplexed so that the same aperture can be used for multiple separate optical paths looking in several directions simultaneously without startracker rotation. Additionally, separate Schmidt corrector plates are not required to compensate for spherical aberration. The optical assembly, or what would normally be considered as the telescope, is less than 20 cc in volume, weighs less than 55 grams, and contains the equivalent of three individual telescopes. Each one has a 4 deg Field of View (FOV) with a field of regard of 48 square degrees. Mini-OWLS has a bandwidth of approximately 300 nm in or near the visible wavelength. The projected resolution of the startracker is 5 to 10 arcseconds, depending on the centroiding algorithm used. The Mini-OWLS program was initiated last year and represents a miniaturized version of a similar design for aeronautical applications. The contract is managed by Wright Laboratory, Air Force Systems Command, Wright-Patterson AFB, Ohio, with funding from the Strategic Defense Initiative Organization through Eglin AFB. The initial phase of the program is to build and test a development unit. The second phase is to integrate the startracker with the Charles Stark Draper Laboratory Micromechanical Inertial Guidance System (MIGS) and the Signal Processing Packaging Design (SPPD) being developed by Texas Instruments. The preliminary design review was conducted in November 1991. Three-axes prototype

  1. Thermal adaptiveness of plumage color in screech owls

    USGS Publications Warehouse

    Mosher, James A.; Henny, Charles J.

    1976-01-01

    Clinal variation in the relative proportions of red and gray plum- age phases in Screech Owls (Otus asio) was analyzed by Owen (1963) and Marshall (1967). This variation was well known prior to Owen's work, but was misinterpreted (Baird, et al. 1874, Hasbrouck 1893, Allen 1893).]Laurel VanCamp and Charles Henny (MS) have 30 years of data on a northern Ohio Screech Owl population. They observed an over- winter decline (from about 25% to 15%) in the proportion of red phase birds in the winter of 1951-52. This decline was correlated with a severe winter of above normal snowfall and below average temperatures. They examined banding and recovery data and found overwinter survival of red and gray birds to be the same except for this one severe winter when 44% more red phase birds were lost than grays (VanCamp and Henny MS). Differential mortality was reported by Gullion and Marshall (1968) for red and gray phase Ruffed Grouse (Bonasa umbellus) where snow conditions for roosting is apparently the critical factor for grouse overwinter survival and is related to predation. Snow- roosting has not, to our knowledge, been observed in Screech Owls. VanCamp and Henny (MS) discuss the observations of Ruffed Grouse and Screech Owls and suggest that possible thermoregulatory differences between red and gray phase birds could account for differential overwinter survival.Our objective was to test for differences between color phase in oxygen uptake at several ambient temperatures. We hypothesized that oxygen uptake would be greater by red phase birds, especially at lower temperatures.

  2. Diets and foraging behavior of northern Spotted Owls in Oregon

    USGS Publications Warehouse

    Forsman, E.D.; Anthony, R.G.; Meslow, E.C.; Zabel, C.J.

    2004-01-01

    We describe local, regional, and annual variation in diets of northern Spotted Owls (Strix occidentalis caurina) in Oregon based on 24 497 prey collected at 1118 owl territories in 1970-2003. The sample included 91.5% mammals, 4.3% birds, 4.1% insects, and 0.1% other prey. The diet included ???131 species, including 49 mammals, 41 birds, 3 reptiles, 1 frog, 1 crayfish, 1 scorpion, 2 snails, and 33 species of insects. On average, 91.9 ?? 0.3% (SE) of prey in the diet were nocturnal animals, 3.3 ?? 0.2% were diurnal, and 4.8 ?? 0.2% were active both day and night. Of the prey captured, 50.5 ?? 0.8% were arboreal, 18.7 ?? 0.7% were scansorial, 4.8 ?? 0.2% were aerial, and 26.0 = 0.7% were terrestrial. Mean mass of prey was 116.6 ?? 6.5 g. Diets varied among owl territories, geographic regions, and years; but were generally dominated by four to six species of nocturnal mammals, including northern flying squirrels (Glaucomys sabrinus), woodrats (Neotoma fuscipes and N. cinerea), red tree voles (Arborimus longicaudus), western red-backed voles (Clethrionomys californicus), deer mice (Peromyscus maniculatus), or gophers (Thomomys spp.). Estimates of dietary evenness were low, indicating diets dominated by a few species of mammals. Forest management practices that produce healthy populations of arboreal and scansorial mammals such as flying squirrels, woodrats, and red tree voles should benefit northern Spotted Owls in Oregon and Washington. ?? 2004 The Raptor Research Foundation, Inc.

  3. Observing the Ultrahigh Energy Universe with OWL Eyes

    NASA Technical Reports Server (NTRS)

    Stecker, F. W.; Krizmanic, J. F.; Barbier, L. M.; Loh, E.; Mitchell, J. W.; Sokolsky, P.; Streitmatter, R. E.

    2004-01-01

    The goal of the Orbiting Wide-field Light-collectors (0WL) mission is to study the origin and physics of the highest energy particles known in nature, the ultra- high energy cosmic rays (UHECRs). The OWL mission consists of telescopes with UV sensitive cameras on two satellites operating in tandem to view in stereo the development of the giant particle showers induced in the Earth s atmosphere by UHECRs. This paper discusses the characteristics of the 0WL mission.

  4. Barn Owl Productivity Response to Variability of Vole Populations.

    PubMed

    Pavluvčík, Petr; Poprach, Karel; Machar, Ivo; Losík, Jan; Gouveia, Ana; Tkadlec, Emil

    2015-01-01

    We studied the response of the barn owl annual productivity to the common vole population numbers and variability to test the effects of environmental stochasticity on their life histories. Current theory predicts that temporal environmental variability can affect long-term nonlinear responses (e.g., production of young) both positively and negatively, depending on the shape of the relationship between the response and environmental variables. At the level of the Czech Republic, we examined the shape of the relationship between the annual sum of fledglings (annual productivity) and vole numbers in both non-detrended and detrended data. At the districts' level, we explored whether the degree of synchrony (measured by the correlation coefficient) and the strength of the productivity response increase (measured by the regression coefficient) in areas with higher vole population variability measured by the s-index. We found that the owls' annual productivity increased linearly with vole numbers in the Czech Republic. Furthermore, based on district data, we also found that synchrony between dynamics in owls' reproductive output and vole numbers increased with vole population variability. However, the strength of the response was not affected by the vole population variability. Additionally, we have shown that detrending remarkably increases the Taylor's exponent b relating variance to mean in vole time series, thereby reversing the relationship between the coefficient of variation and the mean. This shift was not responsible for the increased synchrony with vole population variability. Instead, we suggest that higher synchrony could result from high food specialization of owls on the common vole in areas with highly fluctuating vole populations.

  5. Miniature Optical Wide-Angle-Lens Startracker (Mini-OWLS)

    NASA Technical Reports Server (NTRS)

    Miller, Rick; Coulter, Joe E.; Levine, Seymour

    1993-01-01

    This paper provides a brief overview of the design considerations and the current status of the Miniature Optical Wide-Angle Lens Startracker Program. Mini-OWLS offers a revolutionary alternative to the conventional startracker. It is a small, lightweight, low cost, high performance startracker that can be used in a variety of applications including calibration and alignment of Inertial Measurement Units (IMU's) Mini-OWLS makes use of a strap down design incorporating Holographic Optical Elements (HOES) in place of conventional optics. HOES can be multiplexed so that the same aperture can be used for multiple separate optical paths looking in several directions simultaneously without startracker rotation. Additionally, separate Schmidt corrector plates are not required to compensate for spherical aberration. The optical assembly, or what would normally be considered as the telescope, is less than 20 cc in volume, weighs less than 55 grams, and contains the equivalent of three individual telescopes. Each one has a 4 deg Field of View (FOV) with a field of regard of 48 square degrees. Mini-OWLS has a bandwidth of approximately 300 nm in or near the visible wavelength. The projected resolution of the startracker is 5 to 10 arcseconds, depending on the centroiding algorithm used. The Mini-OWLS program was initiated last year and represents a miniaturized version of a similar design for aeronautical applications. The contract is managed by Wright Laboratory, Air Force Systems Command, Wright-Patterson AFB, Ohio, with funding from the Strategic Defense Initiative Organization through Eglin AFB. The initial phase of the program is to build and test a development unit. The second phase is to integrate the startracker with the Charles Stark Draper Laboratory Micromechanical Inertial Guidance System (MIGS) and the Signal Processing Packaging Design (SPPD) being developed by Texas Instruments. The preliminary design review was conducted in November 1991. Three-axes prototype

  6. Renal pathology in owl monkeys in Plasmodium falciparum vaccine trials.

    PubMed

    Iseki, M; Broderson, J R; Pirl, K G; Igarashi, I; Collins, W E; Aikawa, M

    1990-08-01

    Renal specimens of 16 owl monkeys (Aotus vociferans) were studied by light microscopy and immunohistochemistry during a vaccine trial with recombinant proteins of the ring-infected erythrocyte surface antigen (RESA) of Plasmodium falciparum. Deposition of IgG, C3, and P. falciparum antigens in the mesangium was demonstrated by the peroxidase anti-peroxidase (PAP) method. A relationship between the severity of parasitemia at the time of death and the presence of nephropathy was not apparent.

  7. Endangered Species. Spotted Owl Petition Evaluation Beset by Problems

    DTIC Science & Technology

    1989-02-01

    5Population viability analysis is a technique for determining the likelihood of species extinction under various conditions. Page 8 GAO/RCED-89-79 Spotted...alternative would lead to the species ’ extinction in the foresee- able future. * The draft also evaluated the five conditions the act requires to be...accepted a petition from an environmental organi- zation to list the spotted owl as an endangered species under the Endan- gered Species Act. Pursuant to

  8. Distribution of burrowing owls in east-central South Dakota

    USGS Publications Warehouse

    Shaffer, Jill A; Thiele, Jason P.

    2013-01-01

    Western burrowing owl (Athene cunicularia hypugaea) populations have declined across much of western North America, particularly at the northern and eastern edges of the species’ breeding range (Martell et al. 2001, Murphy et al. 2001, Shyry et al. 2001, Skeel et al. 2001, Klute et al. 2003). In South Dakota, the burrowing owl is a summer resident that historically was relatively common throughout the state, but its range has decreased in recent decades, especially in the eastern half of the state (Whitney et al. 1978, South Dakota Ornithologists’ Union [SDOU] 1991, Peterson 1995). Tallman et al. (2002) described the species as uncommon to locally common in western South Dakota, uncommon in the north-central part of the state, and casual (i.e., not within the species’ normal range, but with 3–10 records in the past 10 years) elsewhere in the eastern half. The burrowing owl is a Species of Greatest Conservation Need (South Dakota Department of Game, Fish and Parks [SDGFP] 2006) and a Level I Priority Species in South Dakota (Bakker 2005).

  9. A Dominance Hierarchy of Auditory Spatial Cues in Barn Owls

    PubMed Central

    Witten, Ilana B.; Knudsen, Phyllis F.; Knudsen, Eric I.

    2010-01-01

    Background Barn owls integrate spatial information across frequency channels to localize sounds in space. Methodology/Principal Findings We presented barn owls with synchronous sounds that contained different bands of frequencies (3–5 kHz and 7–9 kHz) from different locations in space. When the owls were confronted with the conflicting localization cues from two synchronous sounds of equal level, their orienting responses were dominated by one of the sounds: they oriented toward the location of the low frequency sound when the sources were separated in azimuth; in contrast, they oriented toward the location of the high frequency sound when the sources were separated in elevation. We identified neural correlates of this behavioral effect in the optic tectum (OT, superior colliculus in mammals), which contains a map of auditory space and is involved in generating orienting movements to sounds. We found that low frequency cues dominate the representation of sound azimuth in the OT space map, whereas high frequency cues dominate the representation of sound elevation. Conclusions/Significance We argue that the dominance hierarchy of localization cues reflects several factors: 1) the relative amplitude of the sound providing the cue, 2) the resolution with which the auditory system measures the value of a cue, and 3) the spatial ambiguity in interpreting the cue. These same factors may contribute to the relative weighting of sound localization cues in other species, including humans. PMID:20442852

  10. Spatial contrast sensitivity and grating acuity of barn owls.

    PubMed

    Harmening, Wolf M; Nikolay, Petra; Orlowski, Julius; Wagner, Hermann

    2009-07-22

    The eyes of barn owls (Tyto alba pratincola) display very little aberrations, and have thus excellent optical quality. In a series of behavioral experiments, we tested whether this presumably beneficial feature is also reflected at a perceptual level in this species. As fundamental indicators for visual performance, the spatial contrast sensitivity function (CSF) and grating acuity were measured in two barn owls with psychophysical techniques. Stimulus luminance was 2.7 cd/m(2). The CSF found here renders the typical band-limited, inverted U-shaped function, with a low maximum contrast sensitivity of 8-19 at a spatial frequency of 1 cyc/deg. Grating acuity was estimated from the CSF high frequency cut-off and yielded 3.0-3.7 cyc/deg. In a second experiment, in which contrast was held constant and spatial frequency was varied, grating acuity was measured directly (2.6-4.0 cyc/deg). These results put barn owls at the very low end of the visual acuity spectrum of birds, and demonstrate that visual resolution and sensitivity cannot be predicted by optical considerations alone.

  11. A dominance hierarchy of auditory spatial cues in barn owls.

    PubMed

    Witten, Ilana B; Knudsen, Phyllis F; Knudsen, Eric I

    2010-04-28

    Barn owls integrate spatial information across frequency channels to localize sounds in space. We presented barn owls with synchronous sounds that contained different bands of frequencies (3-5 kHz and 7-9 kHz) from different locations in space. When the owls were confronted with the conflicting localization cues from two synchronous sounds of equal level, their orienting responses were dominated by one of the sounds: they oriented toward the location of the low frequency sound when the sources were separated in azimuth; in contrast, they oriented toward the location of the high frequency sound when the sources were separated in elevation. We identified neural correlates of this behavioral effect in the optic tectum (OT, superior colliculus in mammals), which contains a map of auditory space and is involved in generating orienting movements to sounds. We found that low frequency cues dominate the representation of sound azimuth in the OT space map, whereas high frequency cues dominate the representation of sound elevation. We argue that the dominance hierarchy of localization cues reflects several factors: 1) the relative amplitude of the sound providing the cue, 2) the resolution with which the auditory system measures the value of a cue, and 3) the spatial ambiguity in interpreting the cue. These same factors may contribute to the relative weighting of sound localization cues in other species, including humans.

  12. Intraspecific variation in reproductive traits of burrowing owls

    USGS Publications Warehouse

    Conway, Meaghan; Nadeau, Christopher P.; Conway, Courtney J.

    2012-01-01

    Reviews of hatching asynchrony in birds recommended more studies on intraspecific variation in the extent of hatching asynchrony. We examined intraspecific variation in clutch size, laying chronology, onset of incubation, incubation period, and hatching asynchrony in burrowing owls (Athene cunicularia) in the Imperial Valley of California. Mean clutch size was 7.4 eggs and owls averaged 0.5 eggs laid per day. Females varied considerably in laying interval and onset of incubation (range = 1st to 9th egg in the clutch). The mean incubation period was 21.9 days. Hatching interval also varied greatly among females (x = 0.8, range 0.1-2.0 days between successively hatched eggs). Past burrowing owl studies have largely overlooked the substantial intraspecific variation in these traits or have reported estimates that differ from ours. Future studies designed to identify the environmental factors that explain the large intraspecific variation in these traits will likely provide insights into the constraints on local abundance.

  13. The Structure and Noise Reduction Capacity of Owl Down

    NASA Astrophysics Data System (ADS)

    Jaworski, Justin; Clark, Ian; Alexander, Nathan; Devenport, William; Daly, Conor; Peake, Nigel; Glegg, Stewart

    2014-11-01

    Many species of owl rely on specialized plumage to reduce their self-noise levels and enable hunting in acoustic stealth. In contrast to the leading-edge comb and compliant trailing-edge fringe attributes of owls, the aeroacoustic impact of the fluffy down material on the upper wing surface remains largely speculative as a means to eliminate aerodynamic noise across a broad range of frequencies. Photographic analysis of the owl down reveals a unique forest-like structure, whereby the down fibers rise straight up from the wing surface and then bend into the flow direction to form a porous canopy, with an open area fraction of approximately 70%. Experimental measurements demonstrate that the canopy feature reduces dramatically the turbulent pressure levels on the wing surface by up to 30dB, which affects the roughness noise characteristic of the down in a manner consistent with the theory of flows over and through vegetation. Mathematical models developed for the turbulence noise generation by the down fibers and for the mixing-layer instability above the porous canopy furnish a theoretical basis to understand the influence of the down geometric structure on its self-noise signature and noise suppression characteristics.

  14. Features of owl wings that promote silent flight.

    PubMed

    Wagner, Hermann; Weger, Matthias; Klaas, Michael; Schröder, Wolfgang

    2017-02-06

    Owls are an order of birds of prey that are known for the development of a silent flight. We review here the morphological adaptations of owls leading to silent flight and discuss also aerodynamic properties of owl wings. We start with early observations (until 2005), and then turn to recent advances. The large wings of these birds, resulting in low wing loading and a low aspect ratio, contribute to noise reduction by allowing slow flight. The serrations on the leading edge of the wing and the velvet-like surface have an effect on noise reduction and also lead to an improvement of aerodynamic performance. The fringes at the inner feather vanes reduce noise by gliding into the grooves at the lower wing surface that are formed by barb shafts. The fringed trailing edge of the wing has been shown to reduce trailing edge noise. These adaptations to silent flight have been an inspiration for biologists and engineers for the development of devices with reduced noise production. Today several biomimetic applications such as a serrated pantograph or a fringed ventilator are available. Finally, we discuss unresolved questions and possible future directions.

  15. Auditory spatial discrimination by barn owls in simulated echoic conditions

    NASA Astrophysics Data System (ADS)

    Spitzer, Matthew W.; Bala, Avinash D. S.; Takahashi, Terry T.

    2003-03-01

    In humans, directional hearing in reverberant conditions is characterized by a ``precedence effect,'' whereby directional information conveyed by leading sounds dominates perceived location, and listeners are relatively insensitive to directional information conveyed by lagging sounds. Behavioral studies provide evidence of precedence phenomena in a wide range of species. The present study employs a discrimination paradigm, based on habituation and recovery of the pupillary dilation response, to provide quantitative measures of precedence phenomena in the barn owl. As in humans, the owl's ability to discriminate changes in the location of lagging sources is impaired relative to that for single sources. Spatial discrimination of lead sources is also impaired, but to a lesser extent than discrimination of lagging sources. Results of a control experiment indicate that sensitivity to monaural cues cannot account for discrimination of lag source location. Thus, impairment of discrimination ability in the two-source conditions most likely reflects a reduction in sensitivity to binaural directional information. These results demonstrate a similarity of precedence effect phenomena in barn owls and humans, and provide a basis for quantitative comparison with neuronal data from the same species.

  16. Auditory spatial discrimination by barn owls in simulated echoic conditions.

    PubMed

    Spitzer, Matthew W; Bala, Avinash D S; Takahashi, Terry T

    2003-03-01

    In humans, directional hearing in reverberant conditions is characterized by a "precedence effect," whereby directional information conveyed by leading sounds dominates perceived location, and listeners are relatively insensitive to directional information conveyed by lagging sounds. Behavioral studies provide evidence of precedence phenomena in a wide range of species. The present study employs a discrimination paradigm, based on habituation and recovery of the pupillary dilation response, to provide quantitative measures of precedence phenomena in the barn owl. As in humans, the owl's ability to discriminate changes in the location of lagging sources is impaired relative to that for single sources. Spatial discrimination of lead sources is also impaired, but to a lesser extent than discrimination of lagging sources. Results of a control experiment indicate that sensitivity to monaural cues cannot account for discrimination of lag source location. Thus, impairment of discrimination ability in the two-source conditions most likely reflects a reduction in sensitivity to binaural directional information. These results demonstrate a similarity of precedence effect phenomena in barn owls and humans, and provide a basis for quantitative comparison with neuronal data from the same species.

  17. Using detection dogs to conduct simultaneous surveys of northern spotted (Strix occidentalis caurina) and barred owls (Strix varia).

    PubMed

    Wasser, Samuel K; Hayward, Lisa S; Hartman, Jennifer; Booth, Rebecca K; Broms, Kristin; Berg, Jodi; Seely, Elizabeth; Lewis, Lyle; Smith, Heath

    2012-01-01

    State and federal actions to conserve northern spotted owl (Strix occidentalis caurina) habitat are largely initiated by establishing habitat occupancy. Northern spotted owl occupancy is typically assessed by eliciting their response to simulated conspecific vocalizations. However, proximity of barred owls (Strix varia)-a significant threat to northern spotted owls-can suppress northern spotted owl responsiveness to vocalization surveys and hence their probability of detection. We developed a survey method to simultaneously detect both species that does not require vocalization. Detection dogs (Canis familiaris) located owl pellets accumulated under roost sites, within search areas selected using habitat association maps. We compared success of detection dog surveys to vocalization surveys slightly modified from the U.S. Fish and Wildlife Service's Draft 2010 Survey Protocol. Seventeen 2 km × 2 km polygons were each surveyed multiple times in an area where northern spotted owls were known to nest prior to 1997 and barred owl density was thought to be low. Mitochondrial DNA was used to confirm species from pellets detected by dogs. Spotted owl and barred owl detection probabilities were significantly higher for dog than vocalization surveys. For spotted owls, this difference increased with number of site visits. Cumulative detection probabilities of northern spotted owls were 29% after session 1, 62% after session 2, and 87% after session 3 for dog surveys, compared to 25% after session 1, increasing to 59% by session 6 for vocalization surveys. Mean detection probability for barred owls was 20.1% for dog surveys and 7.3% for vocal surveys. Results suggest that detection dog surveys can complement vocalization surveys by providing a reliable method for establishing occupancy of both northern spotted and barred owl without requiring owl vocalization. This helps meet objectives of Recovery Actions 24 and 25 of the Revised Recovery Plan for the Northern Spotted Owl.

  18. Estimates of density, detection probability, and factors influencing detection of burrowing owls in the Mojave Desert

    USGS Publications Warehouse

    Crowe, D.E.; Longshore, K.M.

    2010-01-01

    We estimated relative abundance and density of Western Burrowing Owls (Athene cunicularia hypugaea) at two sites in the Mojave Desert (200304). We made modifications to previously established Burrowing Owl survey techniques for use in desert shrublands and evaluated several factors that might influence the detection of owls. We tested the effectiveness of the call-broadcast technique for surveying this species, the efficiency of this technique at early and late breeding stages, and the effectiveness of various numbers of vocalization intervals during broadcasting sessions. Only 1 (3) of 31 initial (new) owl responses was detected during passive-listening sessions. We found that surveying early in the nesting season was more likely to produce new owl detections compared to surveying later in the nesting season. New owls detected during each of the three vocalization intervals (each consisting of 30 sec of vocalizations followed by 30 sec of silence) of our broadcasting session were similar (37, 40, and 23; n 30). We used a combination of detection trials (sighting probability) and double-observer method to estimate the components of detection probability, i.e., availability and perception. Availability for all sites and years, as determined by detection trials, ranged from 46.158.2. Relative abundance, measured as frequency of occurrence and defined as the proportion of surveys with at least one owl, ranged from 19.232.0 for both sites and years. Density at our eastern Mojave Desert site was estimated at 0.09 ?? 0.01 (SE) owl territories/km2 and 0.16 ?? 0.02 (SE) owl territories/km2 during 2003 and 2004, respectively. In our southern Mojave Desert site, density estimates were 0.09 ?? 0.02 (SE) owl territories/km2 and 0.08 ?? 0.02 (SE) owl territories/km 2 during 2004 and 2005, respectively. ?? 2010 The Raptor Research Foundation, Inc.

  19. Tawny owl (Strix aluco) and Hume's Tawny owl (Strix butleri) are distinct species: evidence from nucleotide sequences of the cytochrome b gene.

    PubMed

    Heidrich, P; Wink, M

    1994-01-01

    The cytochrome b gene of the Tawny Owl (Strix aluco), Hume's Tawny Owl (Strix butleri) and the African wood owl (Strix woodfordii) was amplified by polymerase chain reaction (PCR) and partially sequenced (300 base pairs). Sequences differ substantially (9 to 12% nucleotide substitutions) between these taxa indicating that they represent distinct species, which is also implicated from morphological and biogeographic differences. Using cytochrome b sequences of S. aluco, S. butleri, S. woodfordii, Athene noctua and Tyto alba phylogenetic relationship were reconstructed using the "maximum parsimony" principal (PAUP 3.1.1) and the neighbour-joining method (MEGA).

  20. Observations of wintering Snowy Owls (Nyctea scandiaca) at Logan Airport, East Boston, Massachusetts from 1981-1997

    Treesearch

    Norman Smith

    1997-01-01

    Snowy Owls (Nyctea scandiaca) wintering at Logan International Airport were studied over the 15-year period of 1981-1997. Two-hundred twenty-seven Snowy Owls were banded and color-marked to examine the length of time individual birds stayed at this location and to track the movements elsewhere. Fifty-six owls were re-observed outside of the airport...

  1. Winter Movements and Range Use of Radio-marked Mexican Spotted Owls: An Evaluation of Current Management Recommendations

    Treesearch

    Joseph L. Ganey; William M. Block

    2005-01-01

    We summarized existing knowledge on winter movements and range and habitat use of radio-marked Mexican spotted owls. In light of that information, we evaluated the adequacy of current management guidelines. Seasonal movement or "migration" appears to be a regular feature of the winter ecology of Mexican spotted owls. Most radio-marked owls studied were...

  2. Science verses political reality in delisting criteria for a threatened species: The Mexican spotted owl experience

    Treesearch

    Gary C. White; William M. Block; Joseph L. Ganey; William H. Moir; James P. Ward; Alan B. Franklin; Steven L. Spangle; Sarah E. Rinkevich; J. Robert Vahle; Frank P. Howe; James L. Dick

    1999-01-01

    The Mexican spotted owl (Strix occidentalis lucida) was listed as a threatened species under the Endangered Species Act (ESA) in April 1993 (USDI 1993). Concomitant with the listing of the owl, a recovery team was appointed to develop a plan to recover the owl, allowing for its removal from the list of threatened and endangered species. The recovery plan - "the...

  3. OWL (On-Lie Webstories for Learning): A Unique Web-based Literacy Resource for Primary/Elementary Children.

    ERIC Educational Resources Information Center

    Juliebo, Moira; Durnford, Carol

    2000-01-01

    Describes Online Webstories for Learning (OWL), a Web-based resource for elementary school literacy education that was initially developed for use in the United Kingdom. Discusses the importance of including narrative, how OWL is being adapted for use in other countries, and off-line class activities suggested as part of OWL. (Contains 8…

  4. An update of demographic estimates for the Northern Spotted Owls (Strix occidentalis caurina) from Oregon's Central Coast Ranges

    Treesearch

    James A. Thrailkill; Robert G. Anthony; E. Charles Meslow

    1997-01-01

    Demographic characteristics of the Northern Spotted Owl (Strix occidentalis caurina) were studied on the Eugene District Bureau of Land Management, central Oregon Coast Ranges from 1989-1995. Survival rates were estimated from capture histories of banded owls using Cormack-Jolly-Seber open population models. We banded 233 owls, including 119 that...

  5. OWL (On-Lie Webstories for Learning): A Unique Web-based Literacy Resource for Primary/Elementary Children.

    ERIC Educational Resources Information Center

    Juliebo, Moira; Durnford, Carol

    2000-01-01

    Describes Online Webstories for Learning (OWL), a Web-based resource for elementary school literacy education that was initially developed for use in the United Kingdom. Discusses the importance of including narrative, how OWL is being adapted for use in other countries, and off-line class activities suggested as part of OWL. (Contains 8…

  6. Natal and breeding dispersal of northern spotted owls

    USGS Publications Warehouse

    Forsman, E.D.; Anthony, R.G.; Reid, J.A.; Loschl, P.J.; Sovern, S.G.; Taylor, M.; Biswell, B.L.; Ellingson, A.; Meslow, E.C.; Miller, G.S.; Swindle, K.A.; Thrailkill, J.A.; Wagner, F.F.; Seaman, D.E.

    2002-01-01

    We studied the dispersal behavior of 1,475 northern spotted owls (Strix occidentalis caurina) during banding and radio-telemetry studies in Oregon and Washington in 1985-1996. The sample included 324 radio-marked juveniles and 1,151 banded individuals (711 juveniles, 440 non-juveniles) that were recaptured or resighted after dispersing from the initial banding location. Juveniles typically left the nest during the last week in May and the first two weeks in June (x?? ?? SE = 8 June ?? 0.53 days, n = 320, range = 15 May-1 July), and spent an average of 103.7 days in the natal territory after leaving the nest (SE = 0.986 days, n = 137, range = 76-147 days). The estimated mean date that juveniles began to disperse was 19 September in Oregon (95% CI = 17-21 September) and 30 September in Washington (95% CI = 25 September-4 October). Mean dispersal dates did not differ between males and females or among years. Siblings dispersed independently. Dispersal was typically initiated with a series of rapid movements away from the natal site during the first few days or weeks of dispersal. Thereafter, most juveniles settled into temporary home ranges in late October or November and remained there for several months. In February-April there was a second pulse of dispersal activity, with many owls moving considerable distances before settling again in their second summer. Subsequent dispersal patterns were highly variable, with some individuals settling permanently in their second summer and others occupying a series of temporary home ranges before eventually settling on territories when they were 2-5 years old. Final dispersal distances ranged from 0.6-111.2 km for banded juveniles and 1.8-103.5 km for radio-marked juveniles. The distribution of dispersal distances was strongly skewed towards shorter distances, with only 8.7% of individuals dispersing more than 50 km. Median natal dispersal distances were 14.6 km for banded males, 13.5 km for radio-marked males, 24.5 km for

  7. A Korean Space Situational Awareness Program : OWL Network

    NASA Astrophysics Data System (ADS)

    Park, J.; Choi, Y.; Jo, J.; Moon, H.; Im, H.; Park, J.

    2012-09-01

    We are going to present a brief introduction to the OWL (Optical Wide-field patroL) network, one of Korean space situational awareness facilities. Primary objectives of the OWL network are 1) to obtain orbital information of Korean domestic LEOs using optical method, 2) to monitor GEO-belt over territory of Korea, and 3) to alleviate collisional risks posed to Korean satellites from space debris. For these purposes, we are planning to build a global network of telescopes which consists of five small wide-field telescopes and one 2m class telescope. The network of small telescopes will be dedicated mainly to the observation of domestic LEOs, but many slots will be open to other scientific programs such as GRB follow-up observations. Main targets of 2m telescope not only include artificial objects such as GEO debris and LEO debris with low inclination and high eccentricity, but also natural objects such as near Earth asteroids. We expect to monitor space objects down to 10cm in size in GEO using the 2m telescope system. Main research topics include size distribution and evolution of space debris. We also expect to utilize this facility for physical characterization and population study of near Earth asteroids. The aperture size of the small telescope system is 0.5m with Rechey-Cretian configuration and its field of view is 1.75 deg x 1.75 deg. It is equipped with 4K CCD with 9um pixel size, and its plate scale is 1.3 arcsec/pixel. A chopper wheel is employed to maximize astrometric solutions in a single CCD frame, and a de-rotator is used to compensate field rotation of the alt-az type mount. We have designed a compact end unit in which three rotating parts (chopper wheel, filter wheel, de-rotator) and a CCD camera are integrated, and dedicated telescope/site control boards for the OWL network. The design of 2m class telescope is still under discussion yet is expected to be fixed in the first half of 2013 at the latest. The OWL network will be operated in a fully

  8. Anticoagulant rodenticide exposure and toxicosis in four species of birds of prey presented to a wildlife clinic in Massachusetts, 2006-2010.

    PubMed

    Murray, Maureen

    2011-03-01

    Mortalities among birds of prey from anticoagulant rodenticide (AR) toxicosis have been documented in several countries. Reports on extent of exposure within regions of the United States are limited. This study investigated AR exposure and toxicosis in four species of birds of prey (red-tailed hawks [Buteo jamaicensis], barred owls [Strix varia], eastern screech owls [Megascops asio] and great horned owls [Bubo virginianus]) presented to a wildlife clinic in Massachusetts. The aims of this study are to document the proportion of these four species that died or were euthanized due to their presenting injuries that had detectable amounts of ARs in liver tissue; to identify and quantify ARs present; to describe clinical, postmortem, and histopathologic signs of toxicosis; to evaluate potential sublethal effects of AR exposure; and to associate liver AR level with toxicosis. Birds included in the study were sampled without regard to signs of AR toxicosis. Postmortem examinations were conducted, and liver samples were analyzed for AR residues. Of 161 birds tested, 86% had AR residues in liver tissue. The second-generation AR (SGAR) brodifacoum was identified in 99% of positive birds. Mortality from AR toxicosis was diagnosed in 6% of birds. No indications of sublethal effects of exposure were found, and no association between liver brodifacoum level and signs of toxicosis was apparent. Given the high proportion of birds in this study exposed to ARs, specifically brodifacoum, continued monitoring is warranted as new U.S. Environmental Protection Agency regulations on the sale and use of SGARs are enacted.

  9. Tonometry of normal eyes in raptors.

    PubMed

    Stiles, J; Buyukmihci, N C; Farver, T B

    1994-04-01

    An applanation tonometer was used to estimate intraocular pressure in normal eyes of several species of raptors. No bird had active injury or illness, though some were nonreleasable to the wild because of previous injury. Mean (+/- SD) intraocular pressure was 20.6 (+/- 3.4) mm of Hg in red-tailed hawks (Buteo jamaicensis, n = 10), 20.8 (+/- 2.3) mm of Hg in Swainson's hawks (Buteo swainsoni, n = 6), 21.5 (+/- 3.0) mm of Hg in golden eagles (Aquila chrysaetos, n = 7), 20.6 (+/- 2.0) mm of Hg in bald eagles (Haliaeetus leucocephalus, n = 3), and 10.8 (+/- 3.6) mm of Hg in great horned owls (Bubo virginianus, n = 6). There was no significant difference in intraocular pressure between hawks and eagles. Mean pressure in great horned owls was significantly (P < 0.01) lower than pressure in hawks or eagles. Reliable intraocular pressure readings could not be obtained in barn owls (Tyto alba).

  10. Microscopic effects of predator digestion on the surfaces of bones and teeth.

    PubMed

    Rensberger, J M; Krentz, H B

    1988-09-01

    Concentrations of small fossil mammals are frequently encountered in Cenozoic deposits, but the causes for such accumulations have seldom been determined. In many cases the tooth, jaw, and limb fragments appear to be well-preserved under light microscopy, and it is difficult to differentiate damage due to predator digestion from breakage and abrasion due to physical agents. In order to find more specific evidence of predator digestion, we used a scanning electron microscope (SEM) to examine the surface microstructure of bones and teeth consumed by Bubo virginianus (great horned owl) and Canis latrans (coyote), which prey upon similar species. Effects of digestion were found on all the digested bones and teeth examined. The effects on bone include distinctive sets of pits and fissures, dissolution, and physical polishing. The pits and fissures are apparently caused by solution that commences in canals beneath the surface of the bone. The most conspicuous effects on teeth are island-like pillars of dentin surrounded by deep solution fissures. The effects of digestion by coyote and owl are fundamentally the same but differ in degree of development. Bone digested by the owl shows a greater degree of polishing and rounding of edges but has less extensive fissuring. Wide variation in the degree of surface damage occurs in bones digested by the coyote, even within a single fecal pellet.

  11. Antibody Prevalence and Isolation of Viable Toxoplasma gondii from Raptors in the Southeastern USA.

    PubMed

    Love, David; Kwok, Oliver C; Verma, Shiv Kumar; Dubey, Jitender P; Bellah, Jamie

    2016-07-01

    Raptors are good indicators of the prevalence of Toxoplasma gondii in the environment because they prey on small mammals and birds. These prey species are a major source of infection in domestic cats ( Felis catus ), which shed the environmentally resistant oocysts. We assessed T. gondii infection in 281 opportunistically available raptors at a rehabilitation facility between 2012 and 2014. Antibodies to T. gondii were assayed by a modified agglutination test (cutoff 1:25) and found in serum of 22/71 Red-tailed Hawks ( Buteo jamaicensis ), 25/54 Barred Owls ( Strix varia ), 9/41 Red-shouldered Hawks ( Buteo lineatus ), 13/28 Great Horned Owls ( Bubo virginianus ), 6/20 Broad-winged Hawks ( Buteo platypterus ), 2/16 Eastern Screech Owls (Megascops asio), 12/13 Bald Eagles ( Haliaeetus leucocephalus ), 6/12 Cooper's Hawks ( Accipiter cooperii ), 1/8 Black Vultures ( Coragyps atratus ), and 1/1 Golden Eagle ( Aquila chrysaetos ). Antibodies were not detected in 5 Barn Owls ( Tyto alba ), 3 American Kestrels ( Falco sparverius ), 1 Mississippi Kite ( Ictinia mississippiensis ), and 1 Osprey ( Pandion haliaetus ). Viable T. gondii was isolated from the tissues of 1 antibody-positive Barred Owl and identified as a strain having type II alleles at all 10 loci tested, except one (ToxoDB polymerase chain reaction-restriction fragment length polymorphism genotype 3). Type II strain is the most common strain in the US. Results of this study indicate a high prevalence of T. gondii in some raptor species and the first reported genotyping from a Barred Owl.

  12. Unusual leg malformations in screech owls from a South Carolina Superfund site.

    PubMed

    Albers, P H; Hoffman, D J; Brisbin, I L

    2001-05-25

    In 1995, the discovery of leg malformations in several screech owl (Otis asio) nestlings and in their female parent at a Department of Energy (DOE) Superfund site in South Carolina prompted an investigation into the nature of the observed abnormalities. Surviving nestlings and the female parent were transferred to a captive screech owl breeding colony at the USGS Patuxent Wildlife Research Center, Laurel, MD. The malformed female parent and her offspring were each mated with normal owls from the colony for 3 yr. Matings of the malfored female produced five malformed and six normal owls; all owls produced by matings of normal offspring were normal. Malformed offspring were euthanized when it became apparent that their physical distress precluded survival under normal conditions of colony care. Euthanized owls were necropsied and examined for skeletal development. Detailed descriptions of eight malformed owls are presented. Results of the matings indicated that the leg mafformations were caused by a genetic trait in the female parent that was heterozygous dominant. The characteristic was lethal except in occasional mild manifestations and resembled an extreme form of a dominant abnormality previously described for domestic fowl called duplicate polydactyly. Other reports of skeletal abnormalities in wild birds and potential environmental causes of genetic mutations at the DOE Superfund site are presented. Other studies performed at the DOE Superfund site do not implicate elevated (above background) ionizing radiation from 137Cs, the dominant radionuclide where the owls were captured, as the cause of the mutation. The cause of this genetic abnormality remains unknown.

  13. Prey ecology of Mexican spotted owls in pine-oak forests of northern Arizona

    Treesearch

    William M. Block; Joseph L. Ganey; Peter E. Scott; Rudy M. King

    2005-01-01

    We studied Mexican spotted owl (Strix occidentalis lucida) diets and the relative abundance and habitat associations of major prey species in a ponderosa pine (Pinus ponderosa)–Gambel oak (Quercus gambelii) forest in northcentral Arizona, USA, from 1990 to 1993. The owl’s diet was comprised of 94% mammals by...

  14. Flammulated, boreal, and great gray owls in the United States: A technical conservation assessment

    Treesearch

    G. D. Hayward; J. Verner

    1994-01-01

    Flammulated (Otus flammeolus), boreal (Aegolius funereus), and great gray (Strix nebulosa) owls occur over a broad portion of North America and each is designated as a "sensitive species" in four or more USDA Forest Service regions. The insectivorous flammulated owl is a neotropical migrant requiring...

  15. Vegetation and soils of burrowing owl nest sites in Conata Basin, South Dakota

    Treesearch

    James G. MacCracken; Daniel W. Uresk; Richard M. Hansen

    1985-01-01

    Burrowing Owls (Athene cunicularia) in southwestern South Dakota frequently use the burrows of black-tailed prairie dogs (Cynomys ludovicianus) for nesting and escape cover. Coulombe (1971) emphasized the importance of understanding the role of burrow selection in relation to owl behavior, physiology, and overall ecology. He also...

  16. Estimation of food consumption from pellets cast by captive Ural Owls (Strix uralensis)

    Treesearch

    Aki Higuchi; Manabu T. Abe

    1997-01-01

    There is considerable data in the literature on the diet of the Ural Owl (Strix uralensis) based on pellet analysis. Though it is possible to identify prey items by this method, the volume of food consumption is still unknown. The population of Ural Owls in Japan is declining due to the reduction of old-growth forest and the concurrent loss of...

  17. Barred Owl (Strix varia) nest site characteristics in the boreal forest of Saskatchewan, Canada

    Treesearch

    Kurt M. Mazur; Paul C. James; Shanna D. Frith

    1997-01-01

    Between 1994 and 1996 we located 15 active Barred Owl (Strix varia) nests in the boreal forest of central Saskatchewan, Canada. Eighty-seven percent of Barred Owl nests were located within old mixedwood forest stands. Nest tree species included white spruce (Picea glauca), trembling aspen (Populus tremuloides),...

  18. Breeding dispersal of Mexican Spotted Owls in the Sacramento Mountains, New Mexico

    Treesearch

    Joseph L. Ganey; Darrell L. Apprill; Todd A. Rawlinson; Sean C. Kyle; Ryan S. Jonnes; James P. Ward

    2014-01-01

    Dispersal is a key process influencing population dynamics and gene flow in species. Despite this, little is known about breeding dispersal in threatened Mexican Spotted Owls (Strix occidentalis lucida), here defined as movement of a non-juvenile owl between territories where it had the opportunity to breed. We observed 28 cases of breeding dispersal during a study of...

  19. Population dynamics of the California spotted owl in the Sierra Nevada, California

    Treesearch

    J.A. Blakesley; M.E. Seamans; M.M. Connor; A.B. Franklin; G.C. White; R.J. Gutierrez; J.E. Hines; J.D. Nichols; T.E. Munton; D.W.H. Shaw; J.J. Keane; G.N. Steger; T.L. McDonald

    2010-01-01

    The California spotted owl (Strix occidentalis occidentalis) is the only spotted owl subspecies not listed as threatened or endangered under the United States Endangered Species Act despite petitions to list it as threatened. We conducted a meta-analysis of population data for 4 populations in the southern Cascades and Sierra Nevada, California,...

  20. Distribution, abundance, and habitat use of territorial male Boreal Owls (Aegolius funereus) in northeast Minnesota

    Treesearch

    William H. Lane; David E. Andersen; Thomas H. Nicholls

    1997-01-01

    We conducted nocturnal auditory surveys from 1987-1992 to determine the distribution, abundance, and habitat use of Boreal Owls (Aegolius funereus) in northeast Minnesota. We concentrated our efforts in areas where documented nesting attempts by the owls had occurred, along roadways maintained for winter-time access by motor vehicles, and by...

  1. Association of weather and nest-site structure with reproductive success in California spotted owls

    Treesearch

    Malcolm North; George Steger; Renee Denton; Gary Eberlein; Tom Munton; Ken Johnson

    2000-01-01

    Although the spotted owl (Strix occidentalis) has been intensively studied, factors influencing its reproduction are not well understood. We examined a 9-year demographic study of 51-86 pairs of the California spotted owl (S. o. occidentalis), weather conditions, and forest structure at nest sites in oak (Quercus sp.) woodland and...

  2. The importance of old growth refugia in the Yukon boreal forest to cavity-nesting owls

    Treesearch

    D. H. Mossop

    1997-01-01

    The Yukon's boreal forest is a slow-growing yet dynamic system greatly affected by wildfire. Trees of a diameter and age to accommodate cavity-nesting owls and other larger birds should be rare. An experiment was conducted by erecting just over 100 nest boxes throughout the southern Yukon to test the availability of nest holes for small owls. After 5 years an...

  3. Biological diversity in montane riparian ecosystems: The case of the Mexican spotted owl

    Treesearch

    Angela Hodgson; Peter B. Stacey

    1999-01-01

    Although usually considered to be a bird of old growth mixed conifer forests, the Mexican spotted owl historically occurred in a wide range of habitats from lowland cottonwood bosques to montane canyon systems. In a recent study of habitat use in central New Mexico, we found that owls roost primarily in canyon bottoms, and that they select sites that are characterized...

  4. Ecology and management of the spotted owl in the Pacific Northwest.

    Treesearch

    Ralph J. Gutierrez; Andrew B. tech. eds. Carey

    1985-01-01

    The spotted owl (Strix occidentalis caurina) has been listed as a sensitive species by the Pacific Southwest Region USDA Forest Service. Past and present-studies-and surveys have led to the development of a region-wide network of owl territories to comply with the maintenance of viable populations as required by the National Forest Management Act....

  5. OPTIMAL WELL LOCATOR (OWL): A SCREENING TOOL FOR EVALUATING LOCATIONS OF MONITORING WELLS

    EPA Science Inventory

    The Optimal Well Locator ( OWL) program was designed and developed by USEPA to be a screening tool to evaluate and optimize the placement of wells in long term monitoring networks at small sites. The first objective of the OWL program is to allow the user to visualize the change ...

  6. Sex and age composition of Great Gray Owls (Strix nebulosa), winter 1995/1996

    Treesearch

    Robert W. Nero; Herbert W. R. Copland

    1997-01-01

    In winter 1995/1996, a nearly continent-wide movement of Great Gray Owls (Strix nebulosa) occurred. A sample of 126 owls examined during this period, mainly from northeast of Winnipeg, included a large number from the 1994 hatch-year. If our assumptions regarding molt are correct, 51 birds were from this age class. An inhibited molt condition found...

  7. Sex ratios of fledgling and recaptured subadult spotted owls in the southern Sierra Nevada

    Treesearch

    George N. Steger

    1995-01-01

    Estimates of instantaneous growth rates (A) of spotted owl (Strix occidentalis) populations have been based on demographic data that uniformly assumed an equal sex ratio among fledglings. In this study, sex ratios of subadults, banded as juveniles, and fledgling California spotted owls (S. o. occidentalis) were observed and compared to an assumed 1 : 1 ratio. The...

  8. Summer Professional Development in Chemistry for Inservice Teachers Using OWL Quick Prep

    ERIC Educational Resources Information Center

    Powell, Cynthia B.; Pamplin, Kim L.; Blake, Robert E.; Mason, Diana S.

    2010-01-01

    Secondary teachers participating in summer professional development chemistry workshops in Texas used an online chemistry tutoring program, OWL Quick Prep (Day et al. in OWL: Online Web-based Learning, Brooks-Cole Cengage Learning, Florence, KY, 1997) as a part of the inservice training. Self-reported demographic data were used to identify factors…

  9. "Not in the Middle Ages"?: Alan Garner's "The Owl Service" and the Literature of Adolescence.

    ERIC Educational Resources Information Center

    Hardwick, Paul

    2000-01-01

    Discusses connecting with the Middle Ages in adolescent fiction. Discusses how, in "The Owl Service," Garner addresses a relationship between adolescence in the late twentieth century and an aspect of the past--specifically the Middle Ages. Considers how "The Owl Service" is a story energized by myth, concerning the…

  10. Nest reuse by Northern Spotted Owls on the east slope of the Cascade Range, Washington

    Treesearch

    Stan G. Sovern; Margaret Taylor; Eric D. Forsman

    2011-01-01

    During a long-term demography study of Northern Spotted Owls (Strix occidentalis caurina) in the eastern Cascade Range of Washington State in 1989 to 2008, we documented 276 nests of Northern Spotted Owls at 73 different territories. Of these nests, 90.2% were on platforms, mostly in clumps of deformed limbs caused by dwarf mistletoe (primarily...

  11. Chapter 15. Dynamics of forest communities used by great gray owls

    Treesearch

    James R. Habeck

    1994-01-01

    Great gray owls (Strix nebulosa) inhabit forests, but not all forests possess identical characteristics. To understand the owl, we must understand the dynamics of the vegetation communities that support them. Those dynamics operate differently in the Northern Rocky Mountains and the Cascade-Sierra Nevada complex, both of which are inhabited by great...

  12. 77 FR 14036 - Draft Environmental Impact Statement for Experimental Removal of Barred Owls to Benefit...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-08

    ... viability. The draft environmental impact statement analyzes a no-action alternative and seven action alternatives to experimentally determine if removing barred owls will benefit northern spotted owl populations... alternatives vary by the number and location of study areas, the type of experimental design, duration of study...

  13. Estimating the occupancy of spotted owl habitat areas by sampling and adjusting for bias

    Treesearch

    David L. Azuma; James A. Baldwin; Barry R. Noon

    1990-01-01

    A basic sampling scheme is proposed to estimate the proportion of sampled units (Spotted Owl Habitat Areas (SOHAs) or randomly sampled 1000-acre polygon areas (RSAs)) occupied by spotted owl pairs. A bias adjustment for the possibility of missing a pair given its presence on a SOHA or RSA is suggested. The sampling scheme is based on a fixed number of visits to a...

  14. Testosterone, aggression, and territoriality in male Western Screech-owls (Otus kennicottii): results from preliminary experiments

    Treesearch

    Brian L. Herting; James R. Belthoff

    1997-01-01

    Using a hormone implant protocol, we created treatment groups in which circulating levels of testosterone (T) were increased, decreased, or maintained at normal levels (controls) in male Western Screech-owls (Otus kennicottii). Owls were exposed to tape-recorded vocalizations of a conspecific, to which territory holders responded with aggression....

  15. Demography of Mexican spotted owls in the Sacramento Mountains, New Mexico

    Treesearch

    Joseph L. Ganey; Gary C. White; James P. Ward; Sean C. Kyle; Darrell L. Apprill; Todd A. Rawlinson; Ryan S. Jonnes

    2014-01-01

    Information on population dynamics is key to gauging the status of threatened or endangered species. We monitored demography of a population of threatened Mexican spotted owls (Strix occidentalis lucida) in the Sacramento Mountains, New Mexico from 2003 to 2011. We estimated reproductive output for territorial pairs of owls; used mark-recapture methodology and Pradel...

  16. Chapter 11. Conservation status of boreal owls in the United States

    Treesearch

    Gregory D. Hayward

    1994-01-01

    Previous chapters outlined the biology and ecology of boreal owls as well as the ecology of important vegetation communities based on literature from North America and Europe. That technical review provides the basis to assess the current conservation status of boreal owls in the United States. By conservation status, we mean the demographic condition of the species as...

  17. Summer Professional Development in Chemistry for Inservice Teachers Using OWL Quick Prep

    ERIC Educational Resources Information Center

    Powell, Cynthia B.; Pamplin, Kim L.; Blake, Robert E.; Mason, Diana S.

    2010-01-01

    Secondary teachers participating in summer professional development chemistry workshops in Texas used an online chemistry tutoring program, OWL Quick Prep (Day et al. in OWL: Online Web-based Learning, Brooks-Cole Cengage Learning, Florence, KY, 1997) as a part of the inservice training. Self-reported demographic data were used to identify factors…

  18. Great Gray Owl (Strix nebulosa) breeding habitat use within altered forest landscapes

    Treesearch

    Michael B. Whitfield; Maureen Gaffney

    1997-01-01

    We investigated Great Gray Owl (Strix nebulosa) habitat use in eastern Idaho and northwestern Wyoming. Great Gray Owls were not found in severely altered habitats, but young were fledged in areas where 17 to 26 percent of formerly continuous forest had been clearcut. Average clutch (2.7) and brood (2.3) sizes were comparable to other populations,...

  19. Statistical estimators for monitoring spotted owls in Oregon and Washington in 1987.

    Treesearch

    Tlmothy A. Max; Ray A. Souter; Kathleen A. O' Halloran

    1990-01-01

    Spotted owls (Strix occidentalis) were monitored on 11 National Forests in the Pacific Northwest Region of the USDA Forest Service between March and August of 1987. The basic intent of monitoring was to provide estimates of occupancy and reproduction rates for pairs of spotted owls. This paper documents the technical details of the statistical...

  20. Evaluating desired conditions for Mexican spotted owl nesting and roosting habitat

    Treesearch

    Joseph L. Ganey; Jose M. Iniguez; Shaula Hedwall; William M. Block; James P. Ward; Ryan S. Jonnes; Todd A. Rawlinson; Sean C. Kyle; Darrell L. Apprill

    2016-01-01

    The Mexican spotted owl (Strix occidentalis lucida) was listed as a threatened species in 1993, primarily because of concerns over the loss of late seral forest habitat to timber harvest and wildfire. A recovery plan prepared for this owl subspecies explicitly assumed that nesting (and/or roosting) habitat was a primary factor limiting distribution of Mexican...

  1. OPTIMAL WELL LOCATOR (OWL): A SCREENING TOOL FOR EVALUATING LOCATIONS OF MONITORING WELLS

    EPA Science Inventory

    The Optimal Well Locator ( OWL) program was designed and developed by USEPA to be a screening tool to evaluate and optimize the placement of wells in long term monitoring networks at small sites. The first objective of the OWL program is to allow the user to visualize the change ...

  2. Unique songs of African wood-owls (Strix woodfordii) in the Democratic Republic of Congo.

    Treesearch

    B.G. Marcot

    2007-01-01

    Statistical analysis of African wood-owl (Strix woodfordii) song spectrograms suggest a significantly different song type in Democratic Republic of Congo (DRC), central Africa, than elsewhere in eastern or southern Africa. Songs of DRC owls tend to be consistently shorter in duration and more monotone in overall frequency range. The first note is...

  3. "Not in the Middle Ages"?: Alan Garner's "The Owl Service" and the Literature of Adolescence.

    ERIC Educational Resources Information Center

    Hardwick, Paul

    2000-01-01

    Discusses connecting with the Middle Ages in adolescent fiction. Discusses how, in "The Owl Service," Garner addresses a relationship between adolescence in the late twentieth century and an aspect of the past--specifically the Middle Ages. Considers how "The Owl Service" is a story energized by myth, concerning the…

  4. Emaciation and larval filarioid nematode infection in boreal owls (Aegolius funereus).

    PubMed

    Larrat, Sylvain; Dallaire, André D; Lair, Stéphane

    2012-01-01

    Microfilariae are considered non-pathogenic in wild birds. The objective of the current communication is to report host reactions to microfilarial infection of unusual intensity in emaciated boreal owls (Aegolius funereus). An unusually large number of boreal owls (n = 21) were submitted to the Canadian Cooperative Wildlife Health Center-Quebec Region for post-mortem examination during the winter of 2009. Nineteen out of 21 birds were considered emaciated based on atrophy of adipose tissue and pectoral muscles and suboptimal weight. A microscopic examination of a subset of nine owls revealed the presence of microfilariae in six owls. Three of the birds with a heavy parasite burden had masses of larval nematodes obstructing large vessels of the lungs. The emaciated owls are believed to have died from starvation due to a cyclic decrease in prey abundance in the boreal forest. This cycle also drives winter movements of boreal owls to urbanized areas of southern Quebec, presumably accounting for the large number of birds submitted in 2009. In the most severely infected owls, the extreme microfilarial burden might have caused an alteration in circulatory dynamics, gaseous exchanges and also probably some metabolic cost. Consequently, microfilariae could have significantly contributed to the death of some of these owls.

  5. Of spotted owls, old growth, and new policies: a history since the Interagency Scientific Committee report.

    Treesearch

    Bruce G. Marcot; Jack Ward. Thomas

    1997-01-01

    This paper tracks the recent history of planning, management, and litigation regarding northern spotted owls and their habitat on Federal public lands since the 1989 Interagency Scientific Committee to Address the Conservation of the Northern Spotted Owl (ISC). The ISC report and subsequent plans sparked many economic analyses, appeals, lawsuits, forest management...

  6. Use of protected activity centers by Mexican Spotted Owls in the Sacramento Mountains, New Mexico

    Treesearch

    Joseph L. Ganey; James P. Ward; Jeffrey S. Jenness; William M. Block; Shaula Hedwall; Ryan S. Jonnes; Darrell L. Apprill; Todd A. Rawlinson; Sean C. Kyle; Steven L. Spangle

    2014-01-01

    A Recovery Plan developed for the threatened Mexican Spotted Owl (Strix occidentalis lucida) recommended designating Protected Activity Centers (PACs) with a minimum size of 243 ha to conserve core use areas of territorial owls. The plan assumed that areas of this size would protect " the nest site, several roost sites, and the most proximal and highly-used...

  7. Chapter 1: The cactus ferruginous pygmy-owl: Taxonomy, distribution, and natural history

    Treesearch

    Jean-Luc E. Cartron; W. Scott Richardson; Glenn A. Proudfoot

    2000-01-01

    The cactus ferruginous pygmy-owl (Glaucidium brasilianum cactorum) is a small, cryptic owl that is often difficult to observe. Its natural history and conservation needs are poorly understood. Despite ongoing research in Texas and Arizona, the available information remains limited. In addition, factors influencing demographics (e.g., habitat...

  8. Responses of Mexican spotted owls to low-flying military jet aircraft

    Treesearch

    Charles L. Johnson; Richard T. Reynolds

    2002-01-01

    To investigate the effects of military fixed-wing aircraft training on the behavior of the endangered Mexican spotted owl (Strix occidentalis lucida), we subjected four adults and one juvenile owl to low-altitude, fixed-wing, jet aircraft overflight trials in Colorado in 1996 and 1997. Trials consisted of three sequential fly-bys, each at a greater aircraft speed and...

  9. The California spotted owl: a technical assessment of its current status

    Treesearch

    Jared Verner; Kevin S. McKelvey; Barry R. Noon; R. J. Gutierrez; Gordon I. Jr. Gould; Thomas W. Beck

    1992-01-01

    This report is based an the Final Repart submitted on May 8, 1992 by the Technical Assessment Team to the interagency Steering Committee for the California Spotted Owl Assessment. The 13 chapters cover the assessment of the current status of the California spotted owl, its biology and habitat use, and forests where the subspecies occurs in the Sierra Nevada and...

  10. Using Detection Dogs to Conduct Simultaneous Surveys of Northern Spotted (Strix occidentalis caurina) and Barred Owls (Strix varia)

    PubMed Central

    Wasser, Samuel K.; Hayward, Lisa S.; Hartman, Jennifer; Booth, Rebecca K.; Broms, Kristin; Berg, Jodi; Seely, Elizabeth; Lewis, Lyle; Smith, Heath

    2012-01-01

    State and federal actions to conserve northern spotted owl (Strix occidentalis caurina) habitat are largely initiated by establishing habitat occupancy. Northern spotted owl occupancy is typically assessed by eliciting their response to simulated conspecific vocalizations. However, proximity of barred owls (Strix varia)–a significant threat to northern spotted owls–can suppress northern spotted owl responsiveness to vocalization surveys and hence their probability of detection. We developed a survey method to simultaneously detect both species that does not require vocalization. Detection dogs (Canis familiaris) located owl pellets accumulated under roost sites, within search areas selected using habitat association maps. We compared success of detection dog surveys to vocalization surveys slightly modified from the U.S. Fish and Wildlife Service’s Draft 2010 Survey Protocol. Seventeen 2 km ×2 km polygons were each surveyed multiple times in an area where northern spotted owls were known to nest prior to 1997 and barred owl density was thought to be low. Mitochondrial DNA was used to confirm species from pellets detected by dogs. Spotted owl and barred owl detection probabilities were significantly higher for dog than vocalization surveys. For spotted owls, this difference increased with number of site visits. Cumulative detection probabilities of northern spotted owls were 29% after session 1, 62% after session 2, and 87% after session 3 for dog surveys, compared to 25% after session 1, increasing to 59% by session 6 for vocalization surveys. Mean detection probability for barred owls was 20.1% for dog surveys and 7.3% for vocal surveys. Results suggest that detection dog surveys can complement vocalization surveys by providing a reliable method for establishing occupancy of both northern spotted and barred owl without requiring owl vocalization. This helps meet objectives of Recovery Actions 24 and 25 of the Revised Recovery Plan for the Northern Spotted

  11. The influence of hunger on meal to pellet intervals in barred owls

    USGS Publications Warehouse

    Duke, G.E.; Fuller, M.R.; Huberty, B.J.

    1980-01-01

    1. 1. Barred owls fed at a sub-maintenance (SM) level had significantly (P < 0.01) longer meal to pellet intervals (MPI)/g eaten/kg body weight (BW) than those fed at an above maintenance (AM) level; MPI/g per kg for owls fed at a maintenance (M) level was intermediate but significantly (P < 0.01) different from both SM and AM. 2. 2. During SM feeding, MPI/g per kg gradually increased. 3. 3. The proportion of a meal occurring in a pellet was less in ?hungry? owls whether losing weight (SM) or gaining (AM) as compared to owls maintaining their normal body weight (M). 4. 4. SM fed owls appear to be able to increase digestion time as well as thoroughness of digestion.

  12. Winter ecology of the western burrowing owl (Athene cunicularia hypugaea) in southern Texas 1999-2004

    USGS Publications Warehouse

    Woodin, Marc C.; Skoruppa, Mary K.; Hickman, Graham C.

    2007-01-01

    This study examines the winter ecology of the western burrowing owl (Athene cunicularia hypugaea) in five Texas counties surrounding Corpus Christi, in southern Texas. There is a substantial gap in information on the owl's life cycle during migration and non-breeding winter months; almost all previous research on western burrowing owls has been conducted during the breeding season. The western burrowing owl currently is federally threatened in Mexico, federally endangered in Canada, and in the United States is considered a National Bird of Conservation Concern by the U.S. Fish and Wildlife Service. Topics investigated included status, effectiveness of public outreach, roost sites and use of culverts and artificial burrows, roost site fidelity, diet, contaminant burdens, body mass, and ectoparasites. Early ornithological reports and a museum egg set revealed that burrowing owls once bred in southern Texas and were common in winter; however, since the 1950's they have been reported in relatively low numbers and only during winter. In this study, public outreach increased western burrowing owl detections by 68 percent. Owls selected winter roost sites with small-diameter openings, including culverts less than or equal to 16 centimeters and artificial burrows of 15 centimeters, probably because the small diameters deterred mammalian predators. Owls showed strong roost site fidelity; 15 banded birds stayed at the same roost sites within a winter, and 8 returned to the same site the following winter. The winter diet was over 90 percent insects, with crickets the primary prey. Analyses of invertebrate prey and regurgitated pellets showed that residues of all but 3 of 28 carbamate and organophosphate pesticides were detected at least once, but all were below known lethal concentrations. Mean body mass of western burrowing owls was 168 grams and was highest in midwinter. Feather lice were detected in low numbers on a few owls, but no fleas or other ectoparasites were found.

  13. Genetic divergence analysis of the Common Barn Owl Tyto alba (Scopoli, 1769) and the Short-eared Owl Asio flammeus (Pontoppidan, 1763) from southern Chile using COI sequence.

    PubMed

    Colihueque, Nelson; Gantz, Alberto; Rau, Jaime Ricardo; Parraguez, Margarita

    2015-01-01

    In this paper new mitochondrial COI sequences of Common Barn Owl Tyto alba (Scopoli, 1769) and Short-eared Owl Asio flammeus (Pontoppidan, 1763) from southern Chile are reported and compared with sequences from other parts of the World. The intraspecific genetic divergence (mean p-distance) was 4.6 to 5.5% for the Common Barn Owl in comparison with specimens from northern Europe and Australasia and 3.1% for the Short-eared Owl with respect to samples from north America, northern Europe and northern Asia. Phylogenetic analyses revealed three distinctive groups for the Common Barn Owl: (i) South America (Chile and Argentina) plus Central and North America, (ii) northern Europe and (iii) Australasia, and two distinctive groups for the Short-eared Owl: (i) South America (Chile and Argentina) and (ii) north America plus northern Europe and northern Asia. The level of genetic divergence observed in both species exceeds the upper limit of intraspecific comparisons reported previously for Strigiformes. Therefore, this suggests that further research is needed to assess the taxonomic status, particularly for the Chilean populations that, to date, have been identified as belonging to these species through traditional taxonomy.

  14. Genetic divergence analysis of the Common Barn Owl Tyto alba (Scopoli, 1769) and the Short-eared Owl Asio flammeus (Pontoppidan, 1763) from southern Chile using COI sequence

    PubMed Central

    Colihueque, Nelson; Gantz, Alberto; Rau, Jaime Ricardo; Parraguez, Margarita

    2015-01-01

    Abstract In this paper new mitochondrial COI sequences of Common Barn Owl Tyto alba (Scopoli, 1769) and Short-eared Owl Asio flammeus (Pontoppidan, 1763) from southern Chile are reported and compared with sequences from other parts of the World. The intraspecific genetic divergence (mean p-distance) was 4.6 to 5.5% for the Common Barn Owl in comparison with specimens from northern Europe and Australasia and 3.1% for the Short-eared Owl with respect to samples from north America, northern Europe and northern Asia. Phylogenetic analyses revealed three distinctive groups for the Common Barn Owl: (i) South America (Chile and Argentina) plus Central and North America, (ii) northern Europe and (iii) Australasia, and two distinctive groups for the Short-eared Owl: (i) South America (Chile and Argentina) and (ii) north America plus northern Europe and northern Asia. The level of genetic divergence observed in both species exceeds the upper limit of intraspecific comparisons reported previously for Strigiformes. Therefore, this suggests that further research is needed to assess the taxonomic status, particularly for the Chilean populations that, to date, have been identified as belonging to these species through traditional taxonomy. PMID:26668551

  15. Individual and spatio-temporal variations in the home range behaviour of a long-lived, territorial species.

    PubMed

    Campioni, Letizia; Delgado, María del Mar; Lourenço, Rui; Bastianelli, Giulia; Fernández, Nestor; Penteriani, Vincenzo

    2013-06-01

    Despite the fact that investigations of home range behaviour have exponentially evolved on theoretical, analytical and technological grounds, the factors that shape animal home range behaviour still represent an unsolved question and a challenging field of research. However, home range studies have recently begun to be approached under a new integrated conceptual framework, considering home range behaviour as the result of the simultaneous influences of temporal, spatial and individual-level processes, with potential consequences at the population level. Following an integrated approach, we studied the influence of both external and internal factors on variations in the home range behaviour of 34 radiotagged eagle owl (Bubo bubo) breeders. Home range behaviour was characterised through complementary analysis of space use, movement patterns and rhythms of activity at multiple spatio-temporal scales. The effects of the different phases of the biological cycle became considerably evident at the level of movement patterns, with males travelling longer distances than females during incubation and nestling periods. Both external (i.e. habitat structure and composition) and internal (i.e. sex and health state) factors explained a substantial amount of the variation in home range behaviour. At the broader temporal scale, home range and core area size were negatively correlated with landscape heterogeneity. Males showed (1) smaller home range and core area sizes, (2) more complex home range internal structure and (3) higher rates of movement. The better the physiological condition of the individuals, the simpler the internal home range structure. Finally, inter- and intra-individual effects contributed to shaping space use and movement patterns during the biological cycle. Because of the plurality of behavioural and ecological processes simultaneously involved in home range behaviour, we claim that an integrative approach is required for adequate investigation of its

  16. Life-history tradeoffs and reproductive cycles in Spotted Owls

    USGS Publications Warehouse

    Stoelting, Ricka E.; Gutierrez, R.J.; Kendall, William; Peery, M. Zachariah

    2015-01-01

    The study of tradeoffs among life-history traits has long been key to understanding the evolution of life-history strategies. However, more recently, evolutionary ecologists have realized that reproductive costs have the potential to influence population dynamics. Here, we tested for costs of reproduction in the California Spotted Owl (Strix occidentalis occidentalis), and assessed whether costs of reproduction in year t − 1 on reproduction in year t could be responsible for regionally synchronized biennial cycles in reproductive output. Logistic regression analysis and multistate mark–recapture models with state uncertainty revealed that breeding reduced the likelihood of reproducing in the subsequent year by 16% to 38%, but had no influence on subsequent survival. We also found that costs of reproduction in year t − 1 were correlated with climatic conditions in year t, with evidence of higher costs during the dry phase of the El Niño–Southern Oscillation. Using a simulation-based population model, we showed that strong reproductive costs had the potential to create biennial cycles in population-level reproductive output; however, estimated costs of reproduction appeared to be too small to explain patterns observed in Spotted Owls. In the absence of strong reproductive costs, we hypothesize that observed natural cycles in the reproductive output of Spotted Owls are related to as-yet-unmeasured, regionally concordant fluctuations in environmental conditions or prey resources. Despite theoretical evidence for demographic effects, our analyses illustrate that linking tradeoffs to actual changes in population processes will be challenging because of the potential confounding effects of individual and environmental variation.

  17. Blood oxygen binding properties for the burrowing owl, Athene cunicularia.

    PubMed

    Maginniss, L A; Kilgore, D L

    1989-05-01

    Isocapnic O2 equilibrium curves (O2ECs) were generated for whole blood of 4 adult burrowing owls (Athene cunicularia) using thin film techniques. At in vivo pHa (7.49 +/- 0.02; mean +/- 1 SEM) and 41 degrees C, the PO2 at half saturation (P50) was 42.3 +/- 0.8 Torr. CO2 and fixed acid (H+) Bohr slopes (delta log P50/delta pH) were -0.46 +/- 0.01 and -0.42 +/- 0.02, respectively, demonstrating a small specific CO2 effect. CO2 and H+ Bohr slopes were saturation-independent between 0.1 and 0.9 S. Hill plots for Athene blood were non-linear; the Hill coefficient (n) increased from 2.6 below 0.4 S to 3.4 above 0.6 S. Owl equilibrium data were accurately described by the equation: S = [(7.7 x 10(6]/(P4 + 44P3 - 108P2 + 3.5 x 10(4)P) + 1]-1. This complex O2EC shape may result from Hb heterogeneity; isoelectric focusing showed 4 isoHbs with a molar ratio of 9:1:1:1. This study revealed no apparent adaptations of Athene blood for hypoxic and hypercapnic conditions. We conclude that the observed blood O2 binding properties promote tissue O2 delivery during periods of surface activity. While occupying its burrow, the owl compensates for moderate alterations in inspired gas composition partly through increased ventilation.

  18. What Do Owls, Salamanders, Flycatchers and Cuckoos Have In Common?

    SciTech Connect

    Musgrave, Maria A.

    2016-09-27

    This is an article from the Los Alamos Living magazine. Los Alamos National Laboratory sits on a beautiful and unique landscape that provides important protected habitat to many species, including a few that are federally-listed as threatened or endangered. These species are the Jemez Mountains Salamander, the Mexican Spotted Owl, the Southwestern Willow Flycatcher, the Yellow-billed Cuckoo, and the New Mexico Meadow Jumping Mouse. Part of the job of the Laboratory's wildlife biologists is to survey for these species each year and determine what actions need to be taken if they are found.

  19. Temporal Map Formation in the Barn Owl's Brain

    NASA Astrophysics Data System (ADS)

    Leibold, Christian; Kempter, Richard; van Hemmen, J. Leo

    2001-12-01

    Barn owls provide an experimentally well-specified example of a temporal map, a neuronal representation of the outside world in the brain by means of time. Their laminar nucleus exhibits a place code of interaural time differences, a cue which is used to determine the azimuthal location of a sound stimulus, e.g., prey. We analyze a model of synaptic plasticity that explains the formation of such a representation in the young bird and show how in a large parameter regime a combination of local and nonlocal synaptic plasticity yields the temporal map as found experimentally. Our analysis includes the effect of nonlinearities as well as the influence of neuronal noise.

  20. Focal plane detectors possible detector technologies for OWL/AIRWATCH

    SciTech Connect

    Flyckt, Esso

    1998-06-15

    New satellite-born projects OWL and AIRWATCH will need single-photon focal-plane detectors of a million pixels in a design which is optimized to the focusing optics and electronics at acceptable cost. We discuss different phototube possibilities and their pros and cons with crude cost estimates. We conclude that a multichannel-photomultiplier solution is safe. A better compromise may be to adapt a 6 or 9 inch X-ray image intensifier tube or develop a 12 inch image intensifier for detecting individual photons, and adapt the optics to have many mirror modules. The possibility of developing super-large-area phototubes is also discussed.