31 Wood- coloured feathers help it to merge with its surroundings. Seasonal changes In winter, some birds such as the ptarmigan change colour to blend in with the snowy landscape. As birds moult their feathers every year, the ptarmigan can change colour by shedding one set of feathers and replacing them with another, different- coloured set. Nightjar Daytime hideout The nightjar feeds on insects at dusk, but during the day it sits completely still, looking like a broken branch. It keeps the white patch on its wing hidden in order to stay camouflaged. Debris on woodland floor In summer, the ptarmigan’s brown feathers hide it against the rocks. In winter, its white plumage blends in with the snow.