Aptly named, this common northern grouse is closely associated with thickets of dwarf willow on the tundra at all seasons. It occurs in isolated pairs at the beginning of the nesting season, but gathers in flocks in winter. Molting its body feathers twice a year, it goes from mottled brown or gray in summer to white in winter, so that it's camouflaged at all seasons. In winter its feet are heavily feathered to the tips of the toes; these feathers increase the surface area of the feet and act as "snowshoes," allowing the birds to walk easily over fresh drifts.