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
Rock ptarmigan ptarmigan by about 10%. The male's "song" is a loud croaking. The rock ptarmigan is seasonally camouflaged; its feathers moult from white in winter to brown in spring or summer. The breeding male has greyish upper parts with white wings and under parts. In winter, its plumage becomes completely white except for the black tail. It can be distinguished from the winter willow ptarmigan by habitat—the rock ptarmigan prefers higher elevations and more barren habitat; it is also smaller with a more delicate bill. The rock ptarmigan is a sedentary species which breeds across arctic and subarctic Eurasia and North