Apparently the snowy owl population is quite stable.
Conservation
This species has a large range, with an estimated global Extent of Occurrence of 1,000,000-10,000,000 km2. It has a large global population estimated to be 290,000 individuals (Rich et al. 2003). Global population trends have not been quantified, but populations appear to be stable so the species is not believed to approach the thresholds for the population decline criterion of the IUCN Red List (i.e. declining more than 30% in ten years or three generations). For these reasons, the species is evaluated as Least Concern.
Nyctea scandiaca is an irregular breeder in Greenland, Iceland, Fennoscandia and arctic Russia, with Europe accounting for less than a quarter of its global breeding
range. Its European breeding population is small (as few as 1,400 pairs), but fluctuated widely between 1970-1990. Although populations continued to fluctuate in most European countries during 1990-2000, the species remained broadly stable overall. Nevertheless, its population size still renders it susceptible to the risks affecting small populations.
This large owl has a circumpolar distribution in open tundra between 60 degrees N and 83 degrees N. Its populations fluctuate widely according to climatic conditions and prey density, which fluctuates periodically. The total European population amounts to between 16 and 244 breeding pair, the Russian population not included. During the winter it moves somewhat to the south, and some birds appear irregularly in Scotland where several breeding cases have been recorded since the 1970′s.
While there is little information available about long-term population shifts or trends, most Snowy Owl breeding areas in North America are remote from human disturbance. Of course increased access to Arctic areas allows more shooting of owls. Winter sightings are increasing in some areas of Washington, perhaps because of the development of large agricultural fields that attract rodents and waterfowl.
Snowy Owl (Nyctea scandiaca) » Planet of Birds