Bubo scandiacus (del Hoyo and Collar 2014) was previously listed as B. scandiaca.
AERC TAC. 2003. AERC TAC Checklist of bird taxa occurring in Western Palearctic region, 15th Draft. Available at: #http://www.aerc.eu/DOCS/Bird_taxa_of _the_WP15.xls#.
Cramp, S. and Simmons, K.E.L. (eds). 1977-1994. Handbook of the birds of Europe, the Middle East and Africa. The birds of the western Palearctic. Oxford University Press, Oxford.
del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A. and Fishpool, L.D.C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 1: Non-passerines. Lynx Edicions BirdLife International, Barcelona, Spain and Cambridge, UK.
|2000||Lower Risk/Least Concern|
|1994||Lower Risk/Least Concern|
|1988||Lower Risk/Least Concern|
|Migratory status||full migrant||Forest dependency||Does not normally occur in forest|
|Land mass type||Average mass||-|
|Extent of Occurrence breeding/resident (km2)||38,100,000||medium|
|Extent of Occurrence non-breeding (km2)||80,500,000||medium|
|Number of locations||-|
|Estimate||Data quality||Derivation||Year of estimate|
|No. of mature individuals||28000||poor||estimated||2013|
|Decline (3 years/1 generation past)||-||-||-|
|Decline (5 years/1 generation past)||-||-||-|
|Decline (10 years/1 generation past)||-||-||-|
|Decline (10 years/3 generation future)||30-49||-||-||-|
|Decline (10 years/3 generation past and future)||30-49||-||-||-|
|Number of subpopulations||-||-||-|
|Generation length (yrs)||12.1||-||-||-|
Population justification: The population size was estimated to number approximately 200,000 individuals (Partners in Flight Science Committee 2013) (although there is some uncertainty over whether this refers to individuals or mature individuals), but recently, alternative methodologies have been presented which give far lower figures.
Potapov and Sale (2013) presented a ‘Loose Boid’ method of estimating population size. They concluded that instead of being evenly distributed across the tundra, snowy owls could be found in seven different loose boids or very thinly distributed groups which may move throughout given areas in line with conditions; in particular food availability. The largest of these boids was suggested to be in central northern Canada and could contain 4,000 pairs. In total, they estimated that, on average, each boid may contain 2,000 pairs and so the global population size would be c.14,000 pairs or 28,000 mature individuals, which fits with a maximal estimate of 14,000 females suggested by DNA analyses by Marthinsen et al. (2009). However, they also suggested that the population size could be as low as 7,000-8,000 pairs (Potapov and Sale 2013).
The European population is estimated at 700-2,300 pairs, which equates to 1,400-4,600 mature individuals (BirdLife International 2015).
High rates of population decline have been reported in at least the American and Canadian part of its range, with Rosenberg et al. (2016) estimating a 64% decline in U.S.A. and Canada between 1970 and 2014; with an estimated population in these two countries of <30,000 individuals. Extrapolating backwards this would equate to a decline of c.58% over 3 generations (c.36 years) in the population in these countries.
This trend data can then be used in conjunction with Potapov and Sale’s (2013) ‘Loose Boids’. By sub-dividing the global population into these thinly distributed groups and assuming 4,000 pairs are found in the central northern Canadian Boid, this would then mean that on average c.1,667 pairs are found in each other grouping. One of the other 6 boids proposed by Potapov and Sale (2013) is restricted to North America [on Wrangel Island] and one more may move into North America [ranging from the Indrigirka River in Russia to Victoria Island in Canada]. Therefore, there may be between 5,667 and 7,333 pairs in North America at a given time; equating to 6,667-8,333 pairs outside of this range. Taking a very crude view that declines have only occurred in North America, and extrapolating backwards, the population estimates for this region would equate to global population declines over the past 3 generations in the range of 35.7-41.8%. This is not the case though, as the Snowy Owl is known to have declined in the Western Palearctic (e.g. Portenko 1972; Solheim 1994, 2004; I. J. Øien in litt. 2014; T. Lehtiniemi in litt. 2017), and climate change will be likely having global impacts on this species rather than local impacts. Therefore the global decline over three generations may in fact be more similar to that for North America alone – 58%. It should be noted that Snowy Owl populations do fluctuate (BirdLife International 2015) and so this may affect population trend estimates, but given the estimates presented, and the potential for threats to continue into the future then this species is likely to be undergoing global declines of 30-49% in three generations, or possibly even higher.
|Bermuda (to UK)||V||Extant|
|Faroe Islands (to Denmark)||N||Extant|
|Greenland (to Denmark)||N||Extant||Yes||Yes|
|Iran, Islamic Republic of||V||Extant||Yes|
|Russia (Central Asian)||N||Extant||Yes||Yes|
|St Pierre and Miquelon (to France)||N||Extant||Yes||Yes|
|Svalbard and Jan Mayen Islands (to Norway)||N||Extant||Yes|
|Greenland (to Denmark)||South coast of Germania Land, and Slaedelandet|
|Greenland (to Denmark)||Stordal-Moskusoksefjord-Badlanddal-Loch Fyne-Myggbukta|
|Russia (Central Asian)||Upper and Middle Yuribey|
|Russia (European)||Vaygach island|
|Sweden||Lake Tjålme – Valley of Lais|
|Habitat (level 1)||Habitat (level 2)||Importance||Occurrence|
|Wetlands (inland)||Bogs, Marshes, Swamps, Fens, Peatlands||suitable||breeding|
|Wetlands (inland)||Bogs, Marshes, Swamps, Fens, Peatlands||suitable||non-breeding|
|Wetlands (inland)||Permanent Saline, Brackish or Alkaline Marshes/Pools||suitable||breeding|
|Wetlands (inland)||Permanent Saline, Brackish or Alkaline Marshes/Pools||suitable||non-breeding|
|Altitude||0 - 300 m||Occasional altitudinal limits|
|Threat (level 1)||Threat (level 2)||Impact and Stresses|
|Biological resource use||Fishing & harvesting aquatic resources - Unintentional effects: (subsistence/small scale) [harvest]||Timing||Scope||Severity||Impact|
|Biological resource use||Hunting & trapping terrestrial animals - Intentional use (species is the target)||Timing||Scope||Severity||Impact|
|Ongoing||Minority (<50%)||Negligible declines||Low Impact: 4|
|Climate change & severe weather||Habitat shifting & alteration||Timing||Scope||Severity||Impact|
|Ongoing||Whole (>90%)||Rapid Declines||High Impact: 8|
|Transportation & service corridors||Flight paths||Timing||Scope||Severity||Impact|
|Transportation & service corridors||Roads & railroads||Timing||Scope||Severity||Impact|
|Transportation & service corridors||Utility & service lines||Timing||Scope||Severity||Impact|
|Purpose||Primary form used||Life stage used||Source||Scale||Level||Timing|
|Food - human||-||-||Non-trivial||Recent|
|Other household goods||-||-||Non-trivial||Recent|
|Pets/display animals, horticulture||-||-||International||Non-trivial||Recent|
BirdLife International (2017) Species factsheet: Bubo scandiacus. Downloaded from http://www.birdlife.org on 17/12/2017. Recommended citation for factsheets for more than one species: BirdLife International (2017) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 17/12/2017.