The Willow Ptarmigan (Lagopus lagopus) is a grouse of the mountain mires, famous for its seasonal change of plumage — almost entirely snow-white in winter except for black outer tail feathers and a black bill, and reddish-brown to chestnut, densely dark-mottled, in summer, while the wings stay white year-round. The male carries a bright red, fleshy wattle above the eye, most prominent during display, and the female passes through several distinct plumages in autumn to keep matching the shifting terrain. Its feet are feathered all the way to the toes, an adaptation for life on snow. It measures 37–42 cm, has a wingspan of 55–66 cm and weighs 450–800 g.
The male's call is a booming, laughing "ga-ga-ga-ga-ga," often given during a display flight, together with a rolling "kohwa-kohwa" that carries widely over open mires, especially at dawn and dusk in spring. The Willow Ptarmigan breeds on the ground, laying a large clutch of usually 7–11 eggs in a simple, well-hidden scrape among dwarf shrubs or tussocks, incubated by the female alone while the male stands guard nearby; the precocial chicks follow her soon after hatching and feed mainly on insects in their first weeks for rapid growth. Adults live largely on plant food, with willow buds and shoots the staple winter diet, supplemented by bilberry, crowberry and tender greenery once the snow melts. Found in mountain and near-mountain habitat across northern Sweden, particularly mires and willow thickets in birch forest and the lower alpine zone, it is a resident whose Swedish population — estimated at 100,000–300,000 pairs — fluctuates strongly from year to year in cycles tied to small rodent abundance and predation pressure.
Read about this species in Swedish →