Although it cannot hide behind a tree or bush like its southern relatives, the ptarmigan, which is regarded as a delicious meal by almost every arctic predator, is a master at disappearing. When fall comes to the Arctic, the tundra changes rapidly from dull green and brown to snow white. The ptarmigan has adapted well to this changing habitat. Each fall it moults its brown feathers, and grows a pure-white plumage that renders it almost invisible against the snow. In the spring, it moults again to become mottled brown. The females change colour first, in order to be well camouflaged while sitting on their nests.

Throughout the year, ptarmigans seem to be aware of their colouration – during the moulting season, white ptarmigans tend to sit on snowy areas, whereas brown birds prefer to sit on darker backgrounds where they are better camouflaged.