Somewhat less white partridge. Body length about 35 cm, weight 430-880 g.
For tundra partridge, as for white grouse, seasonal dimorphism is characteristic.
The winter plumage is white, with the exception of the outer tail feathers, which are black, and the black stripe at the base of the beak of the male (hence the other name is the blackhorse).
The summer plumage of the male and female, with the exception of white feathering feathers, mottled – gray-brown with small black dots and strokes, well camouflaging birds on the ground. However, the color of the summer dress is changeable and always corresponds to the color of those rocks on which the bird lives.
It is found in the dry hilly tundra (hence the Russian species name) and the Alpine belt of the Northern Hemisphere mountains, including the Pyrenees and Alps, the mountainous part of Scotland, Scandinavia, Iceland, Greenland, North America, the mountains of Northern Asia (Altai, Hangay) and the mountains of Central Japan.
He prefers bare rocks that are not covered by a bush, and keeps close to the snow line. In Iceland and Greenland, during incubation, these partridges descend to lower sites to have better food.
In the winter, he makes migrations. It feeds on plant food – seeds, kidneys, shoots and berries, chicks – insects.
It is a monogamous bird. The female arranges a nest in bushes on the ground, puts in it 12-20 yellow-red eggs with dark specks and incubates them alone without the help of a male during 24-26 days