Dusky Grouse

The Dusky Grouse is a large, sooty gray-brown grouse of interior western mountain forests, formerly lumped with the Sooty Grouse of the Pacific coast under the name "Blue Grouse" until the two were split into separate species in 2006 based on differences in voice, display, and genetics. Males are dark gray overall with a plain, unbarred gray tail tipped with a narrow, pale terminal band, and during courtship they inflate yellow-to-reddish neck air sacs bordered by white feather bases. Females are mottled gray-brown, providing camouflage while nesting.

Key field marks

• Overall dark gray plumage in males, with a plain gray tail and narrow, pale (often grayish) terminal tail band
• Yellow to orange-red neck air sacs bordered by white-based feathers, visible during display
• Females are mottled gray-brown and best told from Sooty Grouse by range

Similar species

Sooty Grouse is nearly identical but occurs along the Pacific coast rather than in interior mountains, has a wider, more grayish terminal tail band, and gives a lower-pitched series of hoots; the two species' ranges are mostly separated by the dry interior of the Great Basin.

Habitat and Range

Dusky Grouse occupy coniferous and mixed forests in mountainous terrain, often using more open, brushy habitat and forest edge in summer and denser conifer stands in winter.

Range

The species is found through the interior mountain ranges of the western United States and Canada, including the Rocky Mountains and Great Basin ranges from British Columbia and Alberta south to Arizona and New Mexico.

Migration

Dusky Grouse make a modest elevational migration, moving to higher-elevation dense conifer stands in winter to feed on needles and descending to more open, brushy habitat at lower elevations in summer.

Behavior

Males display from elevated perches, often on the ground or a low branch, inflating their neck air sacs and giving a series of deep hoots while performing short flutter flights.

Voice

The male's advertising call is a series of low, muffled hoots, often described as ventriloquial and difficult to pinpoint by ear.

Feeding

In winter, Dusky Grouse feed heavily on conifer needles, switching to a broader diet of leaves, berries, flowers, and insects during the snow-free months.

Nesting and breeding

Females nest on the ground, often at the base of a tree or under low shrubs, and raise the brood alone after mating with a displaying male.