Greater sage-grouse (Centrocercus urophasianus)

Physical description

The greater sage-grouse is the largest North American grouse species. In the breeding season, adult males weigh between 5.5 to 7 pounds, while adult females weigh between 2.9 to 3.7 pounds.

Ecology and life history

Image

Photo by WDFW

Greater sage-grouse require large areas of shrubsteppe habitat dominated by sagebrush. Some degraded habitat that lacks the grass and forb understory needed for nesting and brood rearing is nonetheless suitable for wintering grouse. Greater sage-grouse will also use edges of wheat and alfalfa fields near shrubsteppe habitat.

Sagebrush, grasses, “forbs” (non-woody flowering plants), and insects comprise the annual diet of sage grouse. During the winter, greater sage grouse feed almost exclusively on sagebrush. At other times they also feed on forbs. Sagebrush comprises 60 to 80 percent of the yearly diet of adult sage-grouse and up to 95 to 100 percent of the winter diet. They also eat insects, including ants and grasshoppers, which are essential in the diet of growing chicks. Forbs are important to nesting hens in the pre-laying period and insects are essential for growing chicks.

In the spring, male sage-grouse establish small territories on a lek -- an assembly area where they perform a strutting display to proclaim and defend that territory and attract females. Females incubate a clutch of 6 to 9 eggs in a nest on the ground. Annual adult survival averages 50 to 75 percent, and females may live 8 years or more. Watch greater sage-grouse in the wild in this short video: "Thunder Feathers".

Image

Photo by WDFW

Productive breeding habitat is sagebrush steppe with a diverse herbaceous understory, and springs or wet areas that retain green vegetation in late summer for rearing of growing chicks. Male and female greater sage-grouse gather into flocks in winter, as do hens without broods in early summer. This species generally moves between winter and summer ranges, returning to traditional lek sites in February. Nest predation rates are affected by habitat quality, because grasses help conceal nests.

Geographic range

Historically, greater sage-grouse were distributed throughout much of the western United States in 13 states and along the southern border of three western Canadian provinces. In Washington, the range of greater sage grouse once covered half of the land east of the Cascade Mountains. The species have declined dramatically in both distribution and population size in Washington due to conversion to agriculture or other uses.

The current range of sage-grouse is about 8 percent of the historic range, with the grouse occurring in two relatively isolated areas: one primarily on the Yakima Training Center in south-central Washington and the other centered in the Moses Coulee area of Douglas County in north-central Washington. A small reintroduced population also exists in Lincoln County in 2021, but a recent harsh winter and fires in 2020 may result in extinction of that population. The overall population was estimated to be 744 in 2016, but dropped to 676 in 2019. The estimated population then rose to 775 for 2020, but dropped to 699 for 2021. While this indicates that about 90% of grouse survived the 2020 fires and following winter, the impact of the fires on nesting habitat is expected to result in continued declines in the population.

The map shows estimated historic and current range of greater sage-grouse in Washington prior to translocation efforts. For maps of worldwide distribution and other species' information, check out the International Union for Conservation of Nature - Red List  and NatureServe Explorer. 

Image