Dendragapus obscurus Say, 1823

Text and map from Storch I. (2000) : Grouse Action Plan 2000-2004,
reproduced here with the Editor's agreement

Common names:	Blue grouse	English
	Tétras sombre	French
	Felsengebirgshuhn	German
	Gallo azul	Spanish

photo by Petra Kaczensky, Blue Grouse male, display

photo by I. Storch, Blue Grouse male

Conservation Status

IUCN 1996: Lower risk (least concern).
CITES 1998: not listed in Appendices.
National red data books: not listed.

 Taxonomy

Eight subspecies are recognised (Potapov and Flint 1989; del Hoyo 1994); the four coastal subspecies are morphologically and geographically distinct from the four interior subspecies.

 Distribution

 

Western North America from about 33° to 63° N and 105° to 138° E; mountainous areas and coastal islands. Most populations are locally migratory.

Population size and trend

Blue grouse still occupy most of their original range with some local extinctions due to urban development and agriculture. The species is common throughout its range with spring densities of about 10 adult males per km² in the interior, and mostly between 10-30, but also up to 100 in the coastal populations; however, there also are vast areas where the species is absent or occurs at very low densities. Generally, there is greater variation among populations and years in the coastal than in the interior populations. Populations may greatly increase after fires or clear-cutting and rapidly decline as the tree canopy closes. The subspecies howardi in southern California is now absent from parts of its former range and may be threatened due to small population size. (See Zwickel 1992.)

Habitat and ecology

Blue grouse use a wide range of habitats from sea level to >3600 m in elevation, and from coastal rainforest to shrub and steppe high desert and subalpine and alpine tundra, often moving from summer to winter quarters. They inhabit montane forests with relatively open canopies, forest edge habitats including shrub or grassland habitats up to 2km from the forest edge, and subalpine-alpine ecotones. From north to south, they inhabit some of the coldest and some of the hottest montane habitats of North America. The coastal subspecies also inhabit lowland forests. Aspen communities, especially where they interface with mountain shrub and grassland habitats, are important breeding areas for interior races of blue grouse. Almost all populations winter in conifer forest where conifer needles are the main winter food. In part, the distribution of blue grouse appears to be determined by the interspersion of breeding habitats with a well developed herb, grass, and shrub layer and montane coniferous winter habitats. Many but not all populations breed at lower and winter in higher elevations. Some coastal populations, but less so the inland races, may rapidly increase in numbers following large-scale clear-cutting that may create suitable breeding habitats; populations will decline as the canopy closes. Availability of breeding habitat may in these circumstances be more limiting than availability of winter habitat. (See Zwickel 1992.)

Hunting and cultural importance

The blue grouse is a popular game bird throughout its range. It is shot in autumn both for sport and food; hunting bags comprised some 500.000 birds in the late 1970s. Banding studies suggest that the impact of hunting on the populations is low; apparently, the autumn migration to often poorly accessible winter ranges limits the impact of hunting.

Principal threats

Habitat degradation. Its rugged mountainous habitat has helped to protect the species, so that the long-term perspective for many populations is good. Nevertheless, habitat loss and degradation remain threats. Logging at higher elevations is increasing and may negatively impact winter ranges, but in general, the effects of forestry practices on blue grouse are poorly understood. Grazing by domestic livestock in breeding ranges, particularly in shrub and steppe habitats, may affect reproduction. Fire suppression may lead to the loss of aspen communities and thus important breeding habitats; this particularly affects the inland races of blue grouse. Urban development may lead to local habitat loss and population declines (see Zwickel 1992).

Research needs

Despite some 40 years of study, the ability to predict population levels and trends still is limited. Long-term, basic research is needed with mission-oriented studies applied to immediate management problems. In particular, the effects of forest management and the impact of grazing on population dynamics need to be better understood in order to integrate habitat conservation and land use practices.

Current conservation measures

The blue grouse is partially protected throughout its range; hunting is regulated by defined seasons and bag limits. There are some limited monitoring and habitat preservation programmes.

Priority conservation measures

Integrating habitat preservation and forestry practices is the most important conservation need for the species throughout its range, and particularly in breeding habitats. 

Correspondents:

Jim Bland, Jack Gustafson, Rick Hoffman, Fred Zwickel

 

Key publication

Zwickel, F. C. 1992. Blue grouse. The birds of North America, No. 15. The birds of North America, Inc., Philadelphia, PA.