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GAP Analysis Predicted Distribution Map

Ruffed Grouse (Bonasa umbellus)

Species Code: BOUM

Click to enlarge Range map

= Core Habitat
= Marginal Habitat

Breeding Range Map
The green area shows the predicted habitats for breeding only. The habitats were identified using 1991 satellite imagery, Breeding Bird Atlas (BBA), other datasets and experts throughout the state, as part of the Washington Gap Analysis Project. Habitats used during non-breeding months and migratory rest-stops were not mapped.

Metadata (Data about data or how the map was made)

Click to enlarge distribution map

Other maps & Information:
  • Breeding Bird Atlas
  • NatureMapping observations
    during breeding season
  • NatureMapping observations
    throughout the year

This species is common in hardwood and mixed forests at lower elevations, and at higher elevations along riparian corridors, throughout the forested areas of the state. Where they occur with other grouse, Ruffed Grouse are to be found in microhabitats more characteristic of hardwood areas than coniferous areas, and they exist well in managed forest areas. They are mostly absent from riparian corridors below the Ponderosa Pine zone in the Columbia Basin.

The core areas of use were all forested zones below Silver Fir on the west side and up to and including Grand Fir on the east side. Silver Fir, Mountain Hemlock, Interior Redcedar, Interior Western Hemlock, and Subalpine were peripheral. Good habitats were all forest openings, mixed and hardwood forests, riparian corridors, and west-side agriculture. Since the Ruffed Grouse may occur in patches of deciduous vegetation below our mapping resolution in conifer forests, conifer forests were included knowing there may be smaller pockets of habitat suitable for this Grouse.

Washington breeders represent three subspecies: B. u. castanea of the Olympic Peninsula and southwestern Washington, B. u. sabini of the Puget Trough and western Cascades, and B. u. phaia of eastern Washington. The conversion of mature coniferous forests to second growth hardwood and mixed tracts as a result of logging throughout western Washington has probably led to an increase in the number of the Ruffed Grouse. As the hardwood component of the forest declines with increasing elevation (due to both a decline in logging intensity and the general natural decrease in hardwoods as elevation increases in Washington), the dominant grouse becomes the Blue Grouse. There is quite a bit of overlap between the two species however, with Blue Grouse occurring in moderate-elevation forests, and in mixed forests just above the Puget Trough (along with Ruffed). When the Ruffed occur with the Blue Grouse, they are generally limited to riparian corridors, while Blue Grouse occupy the conifers above. It has been noted that drumming males mostly select mixed hardwood-coniferous forest or pure hardwood forest in association with openings such as clear-cuts, fields, or meadows, and that a shrub layer with vertical structure was more important than one with horizontal structure. Apparently, in western Washington Black Cottonwood, Bigleaf Maple, Vine Maple, and Sitka Spruce are the most important tree species for the Ruffed Grouse.

Translated from the Washington Gap Analysis Bird Volume by Uchenna Bright
Text edited by Gussie Litwer
Webpage designed by Dave Lester