Willow ptarmigan by the fact that it is not generally found above the tree line while the rock ptarmigan prefers more elevated, barren habitat. The summer plumage is browner and in the winter, the male willow ptarmigan lacks the rock ptarmigan's black stripe between the eyes and bill. The white-tailed ptarmigan ("Lagopus leucura") in North America is smaller, has a white tail and finely-barred greyer plumage and lives permanently above the tree line. The distinctive British Isles subspecies "L. l. scoticus" (red grouse) was once considered a separate true British species but is now classified as a sub-species. This moorland bird is
Climate of the Arctic the northern and southern land areas receive their winter snow cover, which combined with the reduced solar radiation at the surface, ensures an end to the warm days those areas may experience in summer. By November, winter is in full swing in most of the Arctic, and the small amount of solar radiation still reaching the region does not play a significant role in its climate. The Arctic is often perceived as a region stuck in a permanent deep freeze. While much of the region does experience very low temperatures, there is considerable variability with both location and season. Winter