Willow ptarmigan a reddish hue to the neck and breast, a black tail and white wings and underparts. It has two inconspicuous wattles above the eyes, which become red and prominent in the breeding season. The female is similar in appearance but lacks the wattles and has brown feathers scattered among the white feathers on the belly. During winter, the plumage of both sexes becomes completely white, except for some black feathers in the tail. Immature birds resemble the adults. The willow ptarmigan can be distinguished from the closely related rock ptarmigan ("Lagopus muta") by its larger size and thicker bill and
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