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result(s) for
"Snowy owl"
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Ookpik : the travels of a snowy owl
Tells the story of Ookpik, a snowy owl, and its first year and struggle to survive.
Book
Successful Management of Open, Contaminated Metacarpal Fractures in an Adult Snowy Owl (Bubo scandiacus) With a Minimal Type II External Skeletal Fixator
An adult, male snowy owl (Bubo scandiacus) was found down and unable to fly in western New York State. Physical examination and radiographs revealed a subacute, open wound and fractured major and minor metacarpals of the right wing. A minimal type II external skeletal fixator (ESF) device was placed on the right major metacarpal bone and the open wound was allowed to granulate and close. After evidence of bone union, the ESF device was removed. The owl performed auto-physiotherapy throughout the process and was released with sustained flight 2 months postoperatively. It was recaptured 7 weeks later and underwent further rehabilitation to allow successful release 11 months after surgical stabilization. To our knowledge, this is the first case report describing use of a type II ESF device on the metacarpus of a bird.
Journal Article
Snowy owl invasion! : tracking an unusual migration
\"A historically large irruption of snowy owls during the winter of 2013-2014 brought them across the eastern US, and farther south than usual. Scientists used this opportunity to attach GPS tracking devices to some snowy owls to increase understanding of their winter behavior and migration.\"-- Provided by publisher.
Book
Why do predators specialize on lemmings? Insights from long-term monitoring in the Norwegian low Arctic
Rodent prey sustains a diverse assemblage of Arctic predators. While lemmings and voles cooccur in large parts of the Arctic, certain predators appear to specialize on lemmings. We elucidate reasons for predators’ specialization on lemmings based on two decades’ monitoring of small rodents and their avian predators in low-Arctic Norway. We focus particularly on the snowy owl ( Bubo scandiacus), which currently is believed to be declining across the Arctic, possibly linked to dampened lemming cycles. While five cyclic vole peaks elicited profound numerical responses of breeding rough-legged hawks ( Buteo lagopus) and long-tailed jaegers ( Stercorarius longicaudus), snowy owls were breeding in the only peak with high abundance of the Norwegian lemming ( Lemmus lemmus) in spring. Lemmings strongly dominated the snowy owls’ diets, while rough-legged hawk diets were dominated by voles. We attribute the snowy owls’ specialization on lemmings to our finding that lemmings have higher supranivean activity than voles when the owls arrive in winter and that lemmings are more exposed in barren tundra habitats where breeding owls hunt in summer. We predict that voles will not be able to replace the crucial role of lemmings as prey to snowy owls and other specialized lemming predators in a warming Arctic climate.
Journal Article
The snowy owl scientist
\"It's July on Alaska's North Slope, and scientist Denver Holt is in Utqiagvik surveying nests. Denver has been coming here since 1992, and the snowy owls he studies have been coming here much longer: thousands of years. With its mix of coastal, low-elevation tundra and a rich presence of lemmings, the North Slope is the only area in Alaska where snowy owls regularly nest. How do snowy owls decide where they will nest? How do they manage to arrive at locations where food will be abundant? What drives the success of these delicate tundra ecosystems? These are the mysteries Denver is trying to solve to help ensure a bright future for these elegant hunters.\" -- Amazon.com.
Book
A fatal case of a captive snowy owl (Bubo scandiacus) with Haemoproteus infection in Japan
Parasites of the genus Haemoproteus are vector-borne avian haemosporidia commonly found in bird species of the world. Haemoproteus infections are typically considered relatively benign in birds. However, some Haemoproteus species cause severe disease and mortality, especially for captive birds removed from their original habitat. In September 2018, a captive 15-year-old snowy owl (Bubo scandiacus), kept in a zoological garden of Japan, died subacutely after presenting leg dysfunction. This case showed significantly low PCV and elevated AST, ALT, CK, and LDH values. Many megalomeronts with prominent morphological characteristics of Haemoproteus were observed in the left leg muscles. Those megalomeronts exhibited multilocular structures and were internally filled with merozoites. A new lineage of Haemoproteus was detected by subsequent PCR for the cytochrome b (cytb) gene of avian haemosporidia from DNA extracted from several organ tissues. The detected lineage was classified in the subgenus Parahaemoproteus and was similar to those from the wild birds inhabiting the region including the study area, suggesting that this snowy owl likely acquired its infection from wild birds. This is the first report of a fatal case of a captive bird with a locally transmitted Haemoproteus infection in Japan. We considered the pathogenicity of this infection in conjunction with the clinical course and hematology results. We surmise that snowy owls may be particularly susceptible to infection with Haemoproteus parasites, and warming northern temperatures may exacerbate the overall health of these and other high latitude birds. Further research into the prevalence of Haemoproteus in wild birds near zoological gardens and potential biting midge vectors is necessary for the ex situ conservation of introduced birds.
Journal Article
It's a snowy owl!
\"Soaring high above the winter skies, it's a snowy owl! This carefully crafted text gives readers a glimpse into the world of snowy owls. Full color visuals, critical thinking questions, and a photo glossary assist first time non-fiction readers.\"-- Provided by publisher.
Book
Factors associated with returns of snowy owls to airports following translocation
Human-dominated environments often include ecological traps for wildlife, such as airports that may be perceived as suitable habitat by grassland birds but reduce fitness because of collisions with aircraft. Birds of prey are often attracted to airports where collisions with aircraft (i.e., bird strikes) are usually fatal for the birds and are a significant threat to flight safety. The snowy owl (Bubo scandiacus) is known for its nomadism, exhibiting unpredictable and highly variable movements during the nonbreeding season, including being a common visitor to airports, which often have high small-mammal populations and mimic flat, open habitats used naturally by owls. Since 2009, the Federal Aviation Administration reported an average of 22 snowy owl deaths annually due to aircraft collisions throughout 55 North American airports. To aid in active management of owls at airports, we assessed relocation data of 42 telemetry-tracked snowy owls from 2000–2020 in the United States and Canada. Owls that returned to the airport after relocation (33%) frequently crisscrossed and perched near runways where they were at risk of strikes. Adult females and immature males were more likely to return than the other sex and age classes, and returns were less likely to occur as the distance between the release site and the airport increased. Owls relocated in open habitats with a greater proportion of wetland and cropland (including grasslands and pasture) land cover classes were also less likely to return. We conclude that inclusion of multiple factors to limit return rates of relocated snowy owls from airport facilities can unspring the ecological trap presented by airports to these owls.
Journal Article
Predation pressure by avian predators suggests summer limitation of small-mammal populations in the Canadian Arctic
Predation has been suggested to be especially important in simple food webs and less productive ecosystems such as the arctic tundra, but very few data are available to evaluate this hypothesis. We examined the hypothesis that avian predators could drive the population dynamics of two cyclic lemming species in the Canadian Arctic. A dense and diverse suite of predatory birds, including the Snowy Owl (
Bubo scandiacus
), the Rough-legged Hawk (
Buteo lagopus
), and the Long-tailed Jaeger (
Stercorarius longicaudus
), inhabits the arctic tundra and prey on collared (
Dicrostonyx groenlandicus
) and brown (
Lemmus trimucronatus
) lemmings during the snow-free period. We evaluated the predation pressure exerted by these predators by combining their numerical (variation in breeding and fledgling numbers) and functional (variation in diet and daily consumption rates) responses to variations in lemming densities over the 2004-2010 period. Breeding density and number of fledglings produced by the three main avian predators increased sharply without delay in response to increasing lemming densities. The proportion of collared lemmings in the diet of those predators was high at low lemming density (both species) but decreased as lemming density increased. However, we found little evidence that their daily consumption rates vary in relation to changes in lemming density. Total consumption rate by avian predators initially increased more rapidly for collared lemming but eventually leveled off at a much higher value for brown lemmings, the most abundant species at our site. The combined daily predation rate of avian predators exceeded the maximum daily potential growth rates of both lemming species except at the highest recorded densities for brown lemmings. We thus show, for the first time, that predation pressure exerted without delay by avian predators can limit populations of coexisting lemming species during the snow-free period, and thus, that predation could play a role in the cyclic dynamic of these species in the tundra.
Journal Article
Breeding Snowy Owls Are Obligate Lemming Predators in Utqiaġvik, Alaska: Results from 30 Years of Study
For 30 years (1992–2021), we collected pellets and pellet fragments and recorded prey cached in Snowy Owl (Bubo scandiacus) nests during the breeding season in Utqiaġvik, Alaska. About 14,000 pellets from an estimated 700 Snowy Owls yielded 43,689 prey items, while caches in 284 nests yielded 3334 prey items. The owls ate thirty-seven species of vertebrates: one species of fish, five species of mammals, and thirty-one species of birds. Based on the pellet analysis, lemmings represented 99.0% of the total prey, with brown lemmings (Lemmus trimucronatus) representing 94.6%, collared lemmings (Dicrostonyx groenlandicus) representing 3.1%, and unidentified lemmings representing 1.3%. All other species were <1%. Based on the prey cached in nests, lemmings represented about 90.0% (89.9%) of the total prey (n = 3334), with brown lemmings representing 88.0% (87.9%), collared lemmings representing 1.9%, and unidentified lemmings representing <1%. Birds represented only 10.0% of the prey cached in nests, although many species were eaten. Food niche breadth (FNB) and dietary evenness (DIEV) scores from pellets were narrow for the prey identified within a group or species. FNB and DIEV scores from the prey cached in nests were also narrow for the prey identified within a group or species. There was almost complete dietary overlap when comparing the prey from pellets with the prey from caches. Biomass estimates from brown lemmings (178 kg) cached in nests were 59 times more than those from collared lemmings (3 kg). Biomass estimates for large birds were misleading, as the owls mainly ate the breast, humerus, and femur muscles. Our study supports a general consensus that Snowy Owls are obligate lemming specialists during the breeding season in Utqiaġvik. In fact, they depend almost entirely on one species of lemming—the brown lemming. Consequently, anthropogenic or natural factors that impact lemming populations and distributions will directly affect Snowy Owl populations.
Journal Article