The Ptarmigan changes its colour to white in the winter. Nature is peculiar. The male stays whiter longer but the female gets its camouflage colours earlier to match the colours of nature. The female needs to go unnoticed while keeping the eggs warm in the nest. The male is white and thus catches the attention of predators, keeping them away from the nest.
This photo is taken in the Icelandic Westfjords in the beginning June, 2012.