Willow ptarmigan (Lagopus lagopus) occupy the boreal and arctic northern hemisphere, and are one of the few bird species that remain in the Arctic year-round. In Alaska and northern Canada, willow ptarmigan are common in areas with patches of dense vegetation, especially where willow (Salix) or birch (Betula) shrubs are abundant. They are also found in sedge-willow (Carex-Salix) marshes, in meadows, along road and forest edges, and on open tundra. Unlike Rock Ptarmigan (L. muta), the species avoids dry, rocky areas. After chicks hatch, birds move to wetter areas, such as marshes and along streams. Willow ptarmigan were selected as a Terrestrial Fine-Filter CE for this assessment because they are an important prey species for gyrfalcon [...]