Grouse, order Galliformes, are popular game birds of the family Tetranidae and are related to the other gallinaceous birds including turkeys and quail. Like their relatives, grause are heavy-bodied, chicken like ground dwellers and have a short, heavy bill and short, rounded wings. They are medium sized, 30.5-88.9 cm (12-35 in) long. The feet and nostrils are covered with feathers. Grouse eat seeds, insects, bark, and buds.
The tetraonids, which include the Ptarmigans, have insulating double feathers and feathered feet; even the toes are feathered in the ptarmigans. So-called snowshoes, shed in summer, are characteristic of some species. Tetraonids also have erectile feathers-rusfts or pinnae-on the sides of the neck, and some have inflatable carvical pouches for producing the booming sounds characteristic of some species. They lay large clutches of eggs. Intestinal ceca harbor bacteria that function in the microbial decomposition of cellulose, prominent in their diet.
The sage grouse feeds primarily on sagebrush. Characteristic of all members of the grouse family are feather covered nostrils and legs. The elaborate courtship of the male the use of a collective display site called a lek.