White-tailed ptarmigan and development of the chicks. This suggests that the hens' food calls assist in enhancing survival rates of juvenile ptarmigans. The young birds remain with their mother throughout the summer and autumn season. The white-tailed ptarmigan is well-camouflaged when on the ground. In his pioneering 1909 book on the subject, "Concealing-Coloration in the Animal Kingdom", the American artist Abbott Thayer wrote: The white-tailed ptarmigan has feathers located on its feet to serve as protection from the extreme cold often experienced in the alpine tundra environment. In addition, these birds have feathers around their nostrils to warm the air prior to
Climate of the Arctic of heat from the subsurface land and ocean (both of which gain heat in summer and release it in winter) to the surface and atmosphere. Arctic days lengthen rapidly in March and April, and the sun rises higher in the sky, both bringing more solar radiation to the Arctic than in winter. During these early months of Northern Hemisphere spring most of the Arctic is still experiencing winter conditions, but with the addition of sunlight. The continued low temperatures, and the persisting white snow cover, mean that this additional energy reaching the Arctic from the sun is slow to have