It is a permanent resident of high altitudes on or above the tree line and is native to Alaska and the mountainous parts of Canada and the western United States.

[4] The genus name Lagopus is derived from Ancient Greek lagos (λαγως), meaning "hare", + pous (πους), "foot", in reference to the bird's feathered legs.

The species name leucura was for a long time misspelt leucurus, in the erroneous belief that the ending of Lagopus denotes masculine gender.

It is a stocky bird with rounded wings, square-ended tail, small black beak and short legs with feathering extending to the toes.

[11] Both sexes maintain white tail and wing feathers all the year and males can be identified by their reddish eyecombs (fleshy growths above the eye), also present year-long.

[10] Its habitat includes areas of boulders, krummholz, snowfields, rock slides, frost-heaved soil and upland herbage.

[10][11] Even in winter it stays in high valleys and mountain slopes where alder, willow, birch and spruce poke through the snow cover.

It may have been native here during the early Pleistocene but became locally extinct due to climate changes with greater snow-cover in spring impacting on its breeding season.

Alternatively, it may have been unable to colonize the Sierra Nevada because of the barriers provided by the Columbia River and the Great Basin, and the low altitudes of the intervening South Cascades.

[6][18] Once fall and winter arrive in the region, the ptarmigan feeds on pine needles, seeds, willow and alder buds and twigs.

[6] Winter food sources have a much higher cellulose content than does summer forage, so the ptarmigan relies on bacteria-aided digestion in the cecum to extract essential nutrients.

[18] A clutch consists of two to eight eggs, which retain a cinnamon color for most of the incubation period, but develop brown spots when they are nearly ready to hatch.

In his pioneering 1909 book on the subject, Concealing-Coloration in the Animal Kingdom, the American artist Abbott Thayer wrote: There is perhaps no other bird which moults as gradually as the Ptarmigan, and this fact goes very far to strengthen the supposition that it has developed a peculiarly fluid and perfect system of protective coloration.

This is because, although populations may be in slight decline, its range is too wide and the total number of birds too large to fit the criteria for being listed as "Vulnerable".

It is not a conservation concern and is abundant in alpine zones across North America, indicating that this region is not undergoing dramatic climatic, temperature, or precipitation shifts.