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
Arctic haze the opposite effect of trapped warmth beneath the cloud cover. During the Arctic winter, however, there is no sunlight to reflect. In the absence of this cooling effect, the dominant effect of changes to Arctic clouds is an increased trapping of infrared radiation from the surface. Ship emissions, mercury, aluminium, vanadium, manganese, and aerosol and ozone pollutants are many examples of the pollution that is affecting this atmosphere, but the smoke from forest fires is not a significant contributor. Some of those pollutants figure among environmental effects of coal burning. Due to low deposition rates, these pollutants are not yet