Plump, chickenlike bird of far northern climes; an adaptable species, residing in open tundra, forest clearings and edges, bogs, moorlands, and willow stands, sometimes even straying into farmland. Plumage changes dramatically throughout the year. In winter, both sexes are pure white with black outer tail feathers. As summer progresses, male develops rich rufous head and neck and brownish back; in winter, lacks black eyeline shown by Rock Ptarmigan. Summer female is paler golden-brown with…