There are about 18 species.
Grouse are henlike terrestrial birds, protectively plumaged in shades of red, brown, and gray.
The nostrils are entirely hidden by feathers, and the legs are partially or completely feathered. Western American grouse include the prairie chicken, Tympanuchus cupido, once common in the East, and the sage grouse, Centrocercus urophasianus. The males of both these species are distinguished by yellow air sacs on the neck that inflate to an enormous size during courtship. European species include the capercaillie and the black grouse. The red grouse is found in Great Britain.