Bubo scandiacus

Former treatment of this species in the monotypic genus Nyctea was based on distinct plumage and weak osteological differences (Ford 1967). Genetic studies, however, indicate that it is best placed within the genus Bubo (Sibley and Ahlquist 1990, Wink and Heidrich 1999, Kang et al. 2018). The specific name is an adjective and changes to agree with the gender of the generic name.

Large Holarctic distribution, but populations believed to be declining; climate change is a long-term threat.

Holarctic. Breeding range includes arctic tundras of the world. In Eurasia: northern Greenland, northern Scandinavia, and northern Russia; rarely to the British Isles and Iceland (Mikkola 1983, Cramp 1985, Potapov and Sale 2013, Holt et al. 2020). In North America: in the western Aleutians, Hall Island (Bering Sea), and from northern Alaska and Canadian Arctic Islands north to Ellesmere Island, south to coastal western Alaska, northern Yukon, northern mainland of the Northwest Territories and Nunavut, northeastern Manitoba, northern Quebec and northern Labrador (summarized in Holt et al. 2020).

When food is available, winters on breeding grounds as far north as 82N, or even moves out onto sea ice to hunt along open leads (Holt et al. 2020). Many individuals winter regularly in north-central North America, as far south as the northern Great Plains (Holt et al. 2020). Irregular winter irruptions move south, occasionally as far south as California, Louisiana, and South Carolina. In Eurasia, irruptions can occur as far south as Iceland, British Isles, northern continental Europe, central Russia, northern China, and Sakhalin (Cramp 1985, summarized in Holt et al. 2020).

Estimated global extent of occurrence is 1,000,000-10,000,000 square kilometers (BirdLife International 2005).

Difficult to define occurrences in this wide-ranging species that moves across its breeding range with changes in food availability.

Climate change is a serious concern. Breeding success is dependent upon lemmings; Kerr and Packer (1998) predicted that the collared lemming (Dicrostonyx groenlandicus) will lose approximately 60 percent of its habitat in Canada due to climate warming. Snowy Owls hunt over pack ice and open leads (polynyas) in the winter, and the loss of sea ice as a result of warming may disperse their prey and impact their winter survival (Holt et al. 2020).

Indigenous harvest may affect local populations but probably does not have the potential for wide-scale impact (Parmelee 1992). Winter fox trapping can significantly impact Snowy Owls through bycatch, but estimates of 100,000 hunted annually in Siberia (Ellis and Smith 1993) need verification (Holt et al. 2020).

Natural enemies are few; arctic fox and wolf prey on adults; skuas and jaegers take eggs and chicks. Many apparently die from starvation during movement southward from the arctic, but collisions with automobiles, utility lines, airplanes, gunshot wounds, and entanglement in fishing tackle are responsible for the majority of reported fatalities (Kerlinger and Lein 1988 in Petersen and Holt 1999, Holt et al. 1999). Exposure also kills many nestlings (up to 3 or 4 chicks per clutch) (Karalus 1987).

Kirk (1995) reports no imminent obvious threats in Canada.