a genus of galliform birds of the family Tetraonidae. In males, the tips of the extreme rectrices are long and curved.

There are two species of Lyrurus: the black grouse and the Caucasian blackcock. The black grouse (L. tetrix) is found in the forest and forest-steppe zones of Europe and Asia. The male is black, with a blue and green gloss and a white speculum on the wing. The extreme rectrices curve to the sides in the shape of a lyre—hence the Latin name Lyrurus. The male ranges from 53 to 57 cm in length and from 1.2 to 1.8 kg in weight. The female is smaller and reddish with dark mottling. The habitat is mixed and deciduous forests with clearings. The mating season begins in early spring, with mating displays in the clearings. The nest is placed on the ground; a clutch contains four to 14 eggs. The female incubates the eggs for a period of 19 to 25 days. The diet consists of catkins (alder and birch), buds, shoots, and berries. In winter the black grouse gathers in roaming flocks. It is a valuable game bird.

The Caucasian blackcock (L. mlokosiewiczi) is native to the Greater and Lesser Caucasus. The male is black and lacks the white speculum; the rectrices are downcurved. Females and first-year males are mottled. The habitat is the subalpine zone at the upper edge of the forest. In winter the birds sometimes move to lower elevations. The Caucasian blackcock is rare and requires protection.