The Rock ptarmigan, known simply as the ptarmigan is an arctic-alpine bird. Indeed, its area of presence has followed the thawing prehistoric glaciers towards northern Europe and at altitude. In the Alps, it is found only above 2,300 m altitude. In order to escape from its predators, the ptarmigan becomes white in winter and in summer its plumage takes on the colours of the rocky ground and shallow grasses that it favours. As a mainly flightless bird, evolution has covered its talons in feathers to prevent heat loss, allowing it to move over snow, effectively giving it snowshœs.