Of all the world’s birds, the ptarmigan is probably the hardiest. It is the only species that never retreats from the tundra, either on mountains or in the Arctic. However cold you might be, the ptarmigan will be somewhere chillier. Its range reaches deep into the Arctic Circle, even in winter, and it breeds as far north as any other bird. It has a number of adaptations to assist in its extreme lifestyle. Its feet are densely and permanently feathered, not just to reduce heat loss from bare areas, but also to help the bird walk in the snow – the feathering increases the foot surface area by a factor of four and makes excellent snow shoes. The rest of the feathers are fluffy at the base (fluffier in winter) to give more effective insulation. In extreme conditions birds will dig snow holes for shelter. They are also somewhat sluggish and eat a vegetarian diet, which is nutritious but doesn’t raise their metabolic rate unduly high.
Extracted from ‘A Bird A Day’ by Dominic Couzens, with illustrations by JJ Audubon, published by Batsford. Order a copy from your local independent bookshop, or chance your arm in next week’s newsletter competition – we’ll have 3 copies to give away.