Striking, widespread and widely recognised, thanks in part to the Harry Potter books, the Snowy Owl Bubo scandiacus was previously listed as Least Concern, the lowest threat category of the IUCN Red List. However, this assessment was based on earlier figures that estimated the global population to number around 200,000 individuals, and the absence of evidence of significant declines.
More recent work by Eugene Potapov, Richard Sale and other researchers suggests that this difficult-to-survey species has a more patchy distribution than previously thought, concentrating in seven loose agglomerations. As a result, the earlier figures have been revised down to c. 14,000 pairs. However, the situation is complicated as the species’ population and range naturally fluctuates in response to the availability of its prey, which during the summer breeding season consists almost exclusively of various larger species of lemmings of the genera Dicrostonyx and Lemmus. In poor years it is now estimated that the global population could drop as low as 7,000 (or perhaps even 5,000) pairs.
Source: Birdlife, 4 Jan 2018