Blue Grouse (Dendragapus obscurus)
Associated Species: Other species that may use habitat in a similar way and/or respond similarly
to threats, management, and conservation activities include American Robin and Hermit Thrush.
Distribution: Blue Grouse reside year-round throughout the Southern and Northern Rocky
Mountains, western Canada, Oregon, and Washington, and northern California.
Habitat Requirements: Blue Grouse inhabit upper elevation shrub habitats, including subalpine
krummholz, and open forests with shrub understory, including mixed-conifer where aspen is
present. Young broods appear to favor mesic areas with lush vegetation and high concentrations
of invertebrate prey. In winter they spend most of their time in conifer trees, especially Douglas-fir.
Ecology: Blue Grouse begin courtship activities in mid April and continue to late May. The peak
of hatching in Colorado is mid June to early July. Young leave the nest within 24 hours after the
last egg has hatched. Their diet consists of leaves, flowers, the berries of a wide variety of herbs
and shrubs (including Arctostaphylos uva-ursi, Vaccinium, Fragaria, Amelanchier, Ribes, Rubus,
Rosa), conifer needles (including Douglas-fir and lodgepole pine, primarily in winter), and
invertebrates (principally ants, beetles, and grasshoppers).
Management Issues and Conservation Recommendations: In dense forests of the Pacific
Northwest, logging often boosts local populations by creating open areas; similar results would
not be expected in Colorado except where forests are very dense, given its generally more open
forests. Logging could reduce thermal cover and food supply (conifer needles). Blue Grouse are
hunted in Colorado; the numbers harvested have dropped steadily since 1979. The decline could
result from fewer birds or from fewer hunters; a lack of research has hampered identifying the
causes of the reported decline.
Status and Reasons for Concern: Blue Grouse are not adequately monitored by the BBS within
Physiographic Area 62, and sample sizes are too small to permit analysis of trends. However,
BBS data for 1966-1996 reveal a statistically significant, survey-wide annual rate of decline (-3.6%; P = 0.02; n = 73 routes). Blue Grouse were present on an average of 6.51% (SE = 1.71)
of the BBS routes run in Physiographic Area 62 in Colorado during 1988-1997, at an average
abundance of 0.07 (SE = 0.02) individuals per route. The mean number of routes run each year
was 21.1 (SE = 3.06). This species is monitored by CDOW.
Biological Objective: Maintain or increase the species' distribution and abundance based on
results of CDOW and MCB monitoring programs.
Selected References: Andrews and Righter 1992, Kingery 1998, Schroeder 1984, Zwickel 1992.