Greater Sage-Grouse

The Greater Sage-Grouse is the largest grouse species in North America and one of the most iconic birds of the western sagebrush landscape. It is a heavy-bodied, mottled gray-brown bird with a long, spiky, pointed tail and a black belly patch. Males are considerably larger than females and develop a striking white breast ruff surrounding a pair of bare, yellow-green air sacs that are inflated during an elaborate strutting courtship display each spring.

The species was split from the smaller Gunnison Sage-Grouse in 2000 and remains widespread, though at greatly reduced numbers and range compared to historical times due to loss and fragmentation of sagebrush habitat.

Key field marks

• Very large size with a mottled gray-brown body and black belly patch
• Long, spiky, pointed tail feathers, especially prominent in displaying males
• Male shows a white breast ruff and inflatable yellow-green air sacs when displaying
• Restricted almost entirely to sagebrush habitat

Similar species

Gunnison Sage-Grouse is smaller, has more strongly barred tail feathers, longer filoplumes on the neck, and a faster, more complex strut, but the two are essentially unidentifiable in the field except by range, as their ranges barely overlap. Sharp-tailed Grouse is smaller, paler, and lacks the black belly patch.

Habitat and Range

Greater Sage-Grouse depend entirely on sagebrush steppe, using dense sagebrush for winter food and cover and adjacent grass- and forb-rich areas for nesting and brood-rearing in summer.

Range

The species occurs across parts of eleven western US states -- including Wyoming, Montana, Nevada, Idaho, Utah, Colorado, and Oregon -- plus small areas of southern Alberta and Saskatchewan, Canada, though its range has contracted by roughly half since European settlement.

Migration

Many populations are partial migrants, moving seasonally between higher-elevation summer range and lower-elevation, wind-scoured winter range where sagebrush remains exposed above the snow.

Behavior

Each spring, males gather at traditional lek sites -- open areas within or adjacent to sagebrush -- where they perform synchronized strutting displays to compete for mating opportunities with visiting females.

Voice

The display includes a distinctive series of low, popping, swishing sounds produced as the male's air sacs inflate and deflate, audible for a considerable distance across quiet sagebrush flats at dawn.

Feeding

Sagebrush leaves form the overwhelming majority of the diet in winter, when the birds subsist almost entirely on this single plant; forbs and insects become more important in spring and summer, especially for growing chicks.

Nesting and breeding

The mating system is a lek-based promiscuous system in which a few dominant males achieve most matings. Females nest alone on the ground, typically under a sagebrush plant within a few miles of the lek, and raise the brood without help from the male.