Lagopus is a small genus of birds in the grouse subfamily, commonly known as ptarmigans. The genus contains three living species with numerous described subspecies, all living in tundra or cold upland areas.
The English-language name ptarmigan is derived from the Scottish Gaelic tàrmachan.

The three species are all sedentary specialists of cold regions.
Willow ptarmigan is a circumpolar boreal forest species, white-tailed ptarmigan is a North American alpine bird, and rock ptarmigan breeds in both Arctic and mountain habitats across Eurasia and North America. All, with the exception of the red grouse, have a white winter plumage that helps them blend into the snowy background. Even their remiges are white, while these feathers are black in almost all birds (even birds that are predominantly white, such as the Bali myna) because melanin makes them more resilient and thus improves flight performance. The Lagopus grouse apparently found it easier to escape predators by not being seen than by flying away.

These are hardy vegetarian birds, but insects are also taken by the developing young. In all species except for the willow ptarmigan, the female takes all responsibility for nesting and caring for the chicks, as is typical with gamebirds.

Willow ptarmigan (also willow grouse and red grouse) Lagopus lagopus
Rock ptarmigan
Lagopus muta
White-tailed ptarmigan Lagopus leucura