Habitat selection by wintering male and female Snowy Owls on the Canadian prairies in relation to prey abundance and a competitor, the Great Horned Owl

et al. 2021

Ibis

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Whereas most migratory animals, such as many birds of prey, return to the same breeding area each summer, nomadic breeders search over large distances to locate breeding areas that vary greatly in location from year to year. Nomadic breeders are assumed to extensively sample patch quality before selecting a summer settlement site (e.g. breeding site) with a high abundance of prey. In addition, patch selection during migration might vary, with immature birds sampling the summer environment for the first time. Here, we examined the migratory movements of a nomadic breeder, the Snowy Owl, to determine whether there are differences in phenology among age and sex classes, and where stopovers occur along their migratory journey. Each owl (n = 24) was equipped with a GPS-GSM transmitter during the overwintering period in the USA and Canada from 2014 to 2018. Movement patterns followed a two-process Poisson distribution, allowing us to separate stopovers from directional flights (i.e. migration). Adults completed migration earlier than immatures, with no difference in number of stopovers or time spent at each stopover. Snowy Owls had a higher probability of having a stopover at the beginning of their migration than at the end. Moreover, stopovers occurred primarily on frozen waterbodies more suitable for foraging or roosting outside of the summer range. We conclude that Snowy Owls use stopovers primarily to build up reserves or to rest during migration and they can potentially select appropriate summer settlement sites via short overflights without extensive sampling of patches during lengthy stopovers.

Section: Location and Function Of Stopoversmentioning

confidence: 99%

Nomadic breeders Snowy Owls (Bubo scandiacus) do not use stopovers to sample the summer environment

Brown

McCabe

et al. 2021

Ibis

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“…Snowy Owls exhibit a diversity of movement strategies throughout the year (McCabe et al 2021). During the non-breeding season, individuals regularly overwinter in the Canadian Prairies and the American Great Plains (Chang & Wiebe 2018), and throughout the entire temperate regions of North America during irruption years (Kerlinger & Lein 1988, Robillard et al 2016, Holt et al 2020. Conversely, some individuals stay in the Arctic throughout winter (Therrien et al 2011, Robillard et al 2018.…”

Section: Introductionmentioning

confidence: 99%

“…2021). During the non‐breeding season, individuals regularly overwinter in the Canadian Prairies and the American Great Plains (Chang & Wiebe 2018), and throughout the entire temperate regions of North America during irruption years (Kerlinger & Lein 1988, Robillard et al . 2016, Therrien et al .…”

Section: Introductionmentioning

confidence: 99%

Long‐term population decline of a genetically homogeneous continental‐wide top Arctic predator

Gousy-Leblanc

Broquet

et al. 2023

Ibis

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Genetic analysis can provide valuable information for conservation programmes by unravelling the demographic trajectory of populations, estimating effective population size or inferring genetic differentiation between populations. Here, we investigated the genetic differentiation within Snowy Owls Bubo scandiacus in North America, a species identified as vulnerable by the IUCN, to (1) quantify connectivity among wintering areas, (2) evaluate current genetic diversity and effective population size, and (3) infer changes in the historical effective population size changes from the last millennia to the recent past. The Snowy Owl, a highly mobile top predator, breeds across the Arctic tundra, a region especially sensitive to current climate change. Using single‐nucleotide polymorphism (SNP)‐based analyses on Snowy Owls sampled across the North American non‐breeding range, we found an absence of genetic differentiation among individuals located up to 4650 km apart. Our results suggest high genetic intermixing and effective dispersal at the continental scale despite documented philopatry to non‐breeding sites in winter. Reconstructing the population demographic indicated that North American Snowy Owls have been steadily declining since the Last Glacial Maximum c. 20 000 years ago, and concurrently with global increases in temperature. Conservation programmes should now consider North American Snowy Owls a single, genetically homogeneous continental‐wide population which is probably sensitive to the long‐term global warming occurring since the Last Glacial Maximum.

Section: Introductionmentioning

confidence: 99%

“…2021). During the non-breeding season, individuals regularly overwinter in the Canadian Prairies and the American Great Plains (Chang & Wiebe 2018), and throughout the entire temperate regions of North America during irruption years (Kerlinger & Lein 1988, Robillard et al . 2016, Therrien et al .…”

Section: Introductionmentioning

confidence: 99%

Long-term population decline of a genetically homogenous continental-wide top Arctic predator

Gousy-Leblanc

Broquet

et al. 2022

Preprint

Self Cite

Genetic analysis can provide valuable information for conservation programs by unraveling the demographic trajectory of populations, by estimating effective population size, or by inferring genetic differentiation between populations. Here, we investigated the genetic differentiation within the Snowy Owl (Bubo scandiacus), a species identified as vulnerable by the IUCN, to (i) quantify connectivity among wintering areas, (ii) to evaluate current genetic diversity and effective population size and (iii) to infer changes in the historical effective population size changes from the last millennia to the recent past. The Snowy Owl, a highly mobile top predator, breeds across the Arctic tundra which is a region especially sensitive to current climate change. Using SNP-based analyses on Snowy Owls sampled across the North American nonbreeding range, we found an absence of genetic differentiation among individuals located up to 4,650 km apart. Our results suggest high genetic intermixing and effective dispersal at the continental scale despite documented philopatry to nonbreeding sites in winter. Reconstructing the population demographic indicated that North American Snowy Owls have been steadily declining since the Last Glacial Maximum ca 20,000 years ago and concurrently with global increases in temperature. Conservation programs should now consider North American Snowy Owls as a single, genetically homogenous continental-wide population which is most likely sensitive to the long-term global warming occurring since the Last Glacial Maximum.