White-tailed ptarmigan wings, square-ended tail, small black beak and short legs with feathering extending to the toes. Adults are long, with the males being only slightly larger than the females. The average weight is . During the summer, the white-tailed ptarmigan is a speckled grayish brown with white underparts, tail and wings. In the fall, the plumage has turned a much more reddish-brown color and white feathers begin to grow through. By winter all the summer brown feathers are lost and the bird is completely white. A further molt in the spring precedes the breeding season and the bird returns to its
Arctic vegetation in the spring, and flower and set seed much sooner than plants that grow in warmer conditions. Their peak metabolic rate also occurs at a much lower temperature than plants from farther south. Compact cushions of vegetation keep the plants close to the warm soil and shield the tender central growing shoot. The height of Arctic plants is also governed by snow depth. Plants that protrude above the snow are subject to strong winds, blowing snow, and being eaten by caribou, muskox, or ptarmigan. Mosses and lichens are common in the Arctic. These plants have the ability to stop growth