Any of three or four species of grouse (genus Lagopus) of cold regions. Ptarmigan plumage changes from white in winter to gray or brown, with barring, in spring and summer. The toes are covered with stiff feathers above and below. The common ptarmigan (L. mutus) occurs throughout the British Isles, Europe, and North America, where it is called rock ptarmigan. Ptarmigans survive winter in the Arctic and on mountaintops by browsing shrubs and scratching up lichens and leaves; they burrow in snow to sleep. Males begin group displays in early spring and then separate and display singly in adjoining territories.
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The Ptarmigan, Lagopus muta, is a medium-sized (31–35 cm or 12–14 inches) gamebird in the grouse family. It is known as Rock Ptarmigan, or colloquially Snow Chicken in North America, where it is the official bird for the territory of Nunavut, Canada. It is a widespread bird in the Arctic Cordillera.
It is a sedentary species, breeding across arctic and subarctic Eurasia and North America (including Greenland) on rocky mountainsides and tundra. There are isolated populations in the mountains of Scotland, the Pyrenees, the Alps, Bulgaria, the Urals, the Pamir Mountains, the Altay Mountains and Japan. During the last ice age, the species was far more widespread in continental Europe (Tomek & Bocheński 2005).
The Ptarmigan is seasonally camouflaged; its feathers moult from white in winter to brown in spring or summer. Breeding males have greyish upper parts with white wings and underparts. In winter, plumage becomes completely white except for the black tail. They can be distinguished from the winter Willow Grouse (Willow Ptarmigan in North America) by habitat—Rock Ptarmigan prefer higher elevations and more barren habitat; they are also smaller in size with a more delicate bill.
Ptarmigan feed primarily on birch and willow buds and catkins when available. They will also take various seeds, leaves, flowers and berries of other plant species. Insects are also taken by the developing young.
The male rock ptarmigan's comb has been the focus of studies regarding sexual selection.
Apart from the comb, male rock-ptarmigan has no other ornaments or displays that are typical for grouses in temperate regions. Studies on other grouses have shown that much variation in comb size and colour exist between the species , and that the combs are used in courtship display, and aggressive interactions between males . Many studies such as have shown that there is a strong correlation between the comb size and the level of testosterone in males, and one report from 1981 showed that the amount of testosterone is correlated to aggressiveness against other males.
Studies on a population of male Rock Ptarmigans in Scarpa Lake, conducted by Brodsky L.M. have shown that during the first year, mating success among males was influenced by comb size and condition, and bigamous males had larger combs than monogamous males. However, the correlation of size disappeared after the first year, but the correlation to comb condition remained. This is consistent with another study of the same population of L.mutus that showed that mating success overall, was correlated to comb condition. Exceptions though were first-time breeders where the size of the comb influenced mating success .