The Rock Ptarmigan (Lagopus muta) is a medium-sized (31–35 cm or 12–14 in.) gamebird in the grouse family. It is known simply as Ptarmigan in Europe and colloquially as Snow Chicken or Partridge in North America, where it is the official bird for the territory of Nunavut, Canada,and the official game bird for the province of Newfoundland and Labrador, Canada A sedentary species, the Rock Ptarmigan breeds across arctic and subarctic Eurasia and North America (including Greenland) on rocky mountainsides and tundra. It is widespread in the Arctic Cordillera and is found in 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.
 
The Rock Ptarmigan is seasonally camouflaged; its feathers moult from white in winter to brown in spring or summer. The breeding male has greyish upper parts with white wings and underparts. In winter, its plumage becomes completely white except for the black tail. It can be distinguished from the winter Willow Grouse (Willow Ptarmigan in North America) by habitat — the Rock Ptarmigan prefers higher elevations and more barren habitat; it is also smaller with a more delicate bill.
 
The male's "song" is a loud croaking. Because of the remote habitat in which it lives, it has only a few predators—such as Golden Eagles-and can be surprisingly tame and approachable.
 
The Rock Ptarmigan feeds primarily on birch and willow buds and catkins when available. It will also take various seeds, leaves, flowers and berries of other plant species. Insects are taken by the developing young.
 
Rock Ptarmigan meat is a popular part of festive meals in Icelandic cuisine. Hunting of Rock Ptarmigans was banned in Iceland in 2003 and 2004 due to its declining population. Hunting has been allowed again since 2005, but is restricted to November and only for personal consumption, i.e. selling Rock Ptarmigan is illegal.
 
Apart from the comb, the male Rock Ptarmigan has no 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 exists between the species, and that the comb is used in courtship display and aggressive interactions between males. Many studies have shown that there is a strong correlation between the comb size and the level of testosterone in males; one report from 1981 showed that the amount of testosterone is correlated to aggressiveness against other males.
 
The male's comb has been the focus of studies regarding sexual selection. Studies of a population of male Rock Ptarmigans in Scarpa Lake, Nunavut, 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. The correlation to 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. muta that showed that mating success overall is correlated to comb condition. Exceptions were first-time breeders, in which the size of the comb influenced mating success
The Ptarmigan's  name, Lagopus, is derived from Ancient Greek λαγως, meaning "hare", + pous (πους), "foot", in preference to the bird's feathered legs .
 
The species name, muta, comes from New Latin and means "mute", referring to the simple croaking song of the male. It was for a long time misspelt mutus, in the erroneous belief that the ending of Lagopus denotes masculine gender. However, as the Ancient Greek term λαγωπους is of feminine gender, and the species name has to agree with that, the feminine muta is correct.
 
The word ptarmigan comes from the Scottish Gaelic tàrmachan, which may be related to the word torm, which means a "murmur". The silent initial p was added in the 17th century through the influence of Greek, especially pteron , "wing", "feather" or "pinion".
 
The Willow Grouse (Lagopus lagopus) or Willow Ptarmigan is a bird of the grouse subfamily. It is a sedentary species, breeding in birch and other forests and moorlands in the tundra of Scotland, Scandinavia, Siberia, and of Alaska and northern Canada. It was the state bird of Alaska until July 20, 2010 when it was replaced by the Puffin
In summer male's plumage is marbled brown, with a reddish hue to the neck and breast, a black tail, and white wings and underparts. It has two inconspicuous wattles above the eyes, which become prominent in the breeding season. The female is similar, but lacks the wattles and has brown feathers strewn all over the belly. In winter, both sexes' plumages become completely white, except for the black tail.
 
They can be distinguished from the Rock Ptarmigan by habitat , larger size and thicker bill; the summer plumage is browner, the winter Willow Ptarmigan's male lacks the black loral stripe.
 
The very distinctive British subspecies Red Grouse has sometimes been considered a separate species. This moorland bird is reddish brown all over, except the white feet.
 
The male's call is a loud go-back go-back.
 
White-tailed Ptarmigan, Lagopus leucura, is the smallest bird in the grouse family. It is found in the mountains of western United States, Canada and Alaska.
 
The White-tailed Ptarmigan is the smallest of the ptarmigans and is smaller than the Ruffed Grouse. Adults are 11.8 to 12.2 inches (30 to 31 cm) long, with males only slightly larger than females. The average weight is 11.6 to 16.9 ounces  In dead of winter, this bird is pure white except for a black beak and eyes. In summer, it has a mottled and barred brown head, breast, and back with white wings, belly, and tail.
 
White-tailed Ptarmigan are so named because they are the only ptarmigan with no black on the tail. The tail is white during all seasons of the year. In fall, during the U.S. hunting season, both sexes are mostly pale cinnamon-rufous above with fine spotting and vermiculations to brownish black. A few breast feathers are usually white and the belly, tail, and wings are white. It makes soft, low hoots and low clucking noises.
 
The White-tailed Ptarmigan is the only bird in the alpine zone to remain there during winter, instead of migrating. It has feathers around its nostrils so the air that it breathes in is warm before it reaches its body. The white feathers also helps camouflage it.
 
The White-tailed Ptarmigan is an alpine species, a permanent resident of the high mountains above the timber line, during most of the year. It occupies open country and flies a great deal more than forest grouse, but still prefers running to flying. It ranges from Alaska and western Canada south to northern New Mexico.
 
The White-tailed Ptarmigan has been introduced into the Sierra Nevada Mountains of California, Wallowa Mountains in Oregon, and Uinta Mountains of Utah.
 
Males return from their timberline wintering areas to establish territories on spruce-willow timberline breeding grounds in April. Females arrive in early May and pairs are formed. Four to eight buff, faintly spotted eggs are laid in a hollow on the ground lined with a small amount of grass, leaves, and feathers. Males remain with the females until the eggs are hatched after an incubation period of 23 days.
 
This species' winter food is primarily willow buds. Alpine areas lacking willow cannot support ptarmigan for long. In spring, the leaves and flowers of several forbs are eaten, but willow remains an important part of the diet. In summer, broods may also feed on insects and bulbils of knotweed. It eats grit to help digest its food.
 
The Ptarmigan's genus name, Lagopus, is derived from Ancient Greek lagos (λαγως), meaning "hare", + pous (πους), "foot", in reference to the bird's feathered legs (see also Snowshoe Hare). The species name leucura was for a long time misspelt leucurus, in the erroneous belief that the ending of Lagopus denotes masculine gender. However, as the Ancient Greek term λαγωπους is of feminine gender, and the species name has to agree with that, the feminine leucura is correct. The species name leucura is derived from the Latinized version of the Greek leukos, meaning "white", + oura, meaning "tail"., in reference to the bird's white tail year around