Willow ptarmigan with willow and alder trees, heather moors, tundra and mountain slopes. In the winter, females and sub-adults may move to lower altitudes and seek shelter in valleys or in more densely vegetated areas, but adult males usually remain in the subalpine region. The red grouse is common on heather-clad moorland across the north and west of Great Britain and in localised areas of Ireland. The willow ptarmigan has a varied and seasonal diet. The bird is herbivorous for most of its life and subsists on various plant materials. As juveniles, they may feed on insects due to an inability to
Arctic hare new fur, from brown or grey in the summer to white in the winter, like some other Arctic animals including ermine and ptarmigan, enabling it to remain camouflaged as their environments change. However, the Arctic hares in the far north of Canada, where summer is very short, remain white all year round. The Arctic hare is one of the largest living lagomorphs. On average, this species measures from long, not counting a tail length of . The body mass of this species is typically between , though large individuals can weigh up to . The Arctic hare is a herbivore,