Category: Status Reports
Published: March 1998
Author(s): David W. Hays, Michelle J. Tirhi and Derek W. Stinson
Sage grouse were historically distributed throughout much of the western United States and the southern border of three western Canadian provinces. Their range followed the distribution of sagebrush in the climax sagebrush and prairie ecosystems. From 1900 to the 1930's, sage grouse populations steadily declined throughout North America. From 1940 to 1950, sage grouse declines stabilized but remained permanently reduced because of habitat loss and degradation.
In Washington, sage grouse historically ranged from the Columbia River, north to Oroville, west to the foothills of the Cascades, and east to the Spokane River. By 1860, sage grouse had declined and were rarely seen in some areas that had formerly contained numerous birds. By the early 1900s, sage grouse had been extirpated from Spokane, Columbia, and Walla Walla Counties and perhaps other counties that historically contained small populations. The breeding population in Lincoln County was essentially eliminated by 1985 because of habitat alteration. The sage grouse population on the Fitzner and Eberhardt Arid Lands Ecology Reserve at Hanford (Hanford Site) in Benton County has evidently been extirpated due to catastrophic fires in 1981 and 1984. No sage grouse have been found there in recent surveys. The Badger Pocket area of Kittitas County historically supported large numbers of sage grouse, but they were extirpated by 1987 due to conversion of shrub steppe to agriculture in the 1970's and 1980's.
Recent surveys indicate there are 2 relatively isolated sage grouse populations remaining in Washington. One population is found in Douglas and Grant counties, predominantly on private land. The other population is found on the federally managed Yakima Training Center in Kittitas and Yakima counties which, together with the Hanford site, comprise the largest block of shrub steppe remaining in Washington. These sage grouse populations are isolated from surrounding populations in Idaho and Oregon.
The reduction in sage grouse numbers and distribution in Washington is primarily attributed to loss and degradation of habitat through conversion to agriculture and other land uses. Before the arrival of early settlers, the climax condition in the shrub steppe region of eastern Washington consisted of tracts of native sagebrush and bunchgrass species. Agricultural expansion, overgrazing, and sagebrush control through burning, mechanical removal, and chemical control, severely degraded sage grouse habitat. Approximately 40% remains of the estimated 4.16 million ha (10.4 million acres) of shrub steppe that existed in eastern Washington before European settlement. Sage grouse habitat is a subset of this remaining acreage, and factors affecting occupancy include elevation, slope, soil type, size of shrub steppe patch, and habitat quality.
Sources of mortality of sage grouse include predation, weather, accidents, disease and parasitism, and environmental hazards such as pesticides. These natural and man-influenced factors become more important management issues with small populations. Predation is a limiting factor throughout the annual sage grouse cycle, but its severity depends on habitat quality. Raptors and coyotes are the primary predators of sage grouse while corvids, badgers, and ground squirrels are the most important nest predators. Weather can influence nesting success and survival of young chicks. Diseases and parasites do not appear to be a significant source of mortality.
Sage grouse have survived in Washington in part because portions of the land in Douglas County are poorly suited to agriculture, and in part because military ownership of the Yakima Training Center prevented agriculture and most other development. Sage grouse habitat has improved on lands under the federal Conservation Reserve Program (CRP). Sage grouse populations have increased in Douglas County since 1992. This may represent improving habitat conditions or the cyclical nature of sage grouse populations evident in past years.
Listing sage grouse may be of concern for private landowners due to fears of regulation. However, listing will be a benefit to many landowners interested in enrolling lands in the federal CRP program, as concerns for sage grouse habitat increase the likelihood of land being enrolled. CRP contracts for approximately 785,000 acres in Washington expired in 1997. Applications for re-enrollment were submitted for 591,000 acres, and 483,000 were accepted (82%). The removal of important habitat in Grant and Douglas counties from the CRP program would reverse habitat gains in recent years, and could cause further declines in sage grouse numbers.
Lek counts and harvest information indicate a serious decline in the sage grouse population in Washington. Harvests averaged 1,842 sage grouse from 1951 to 1973, moved below 1,000 after 1974, and declined to 18 in 1987. The season was closed in 1988. The number of males per active lek declined statewide from 35 males/lek in 1970 to 16 males/lek in 1997. One factor that may exaggerate this trend is that the leks added to the count later in the period may have been smaller.
The statewide breeding population of sage grouse in Washington in 1997 was estimated to be approximately 900-1000 birds. About 600 sage grouse are located in Douglas County and 300 -400 are located in Kittitas and Yakima counties. Scattered sage grouse also exist on the periphery of the range but are not believed to play a significant role in the dynamics of the population in Washington.
Management activities in Washington include annual surveys by the Department of Fish and Wildlife to monitor populations, development of a management plan for sage grouse, acquisition and restoration of habitat, and coordination of activities with other land management agencies. Research has and will continue to be conducted on both populations. A conservation agreement with the U.S. Army and U.S. Fish and Wildlife Service has been developed for management of sage grouse habitat on the Yakima Training Center.
The sage grouse population and corresponding sage grouse habitat in Washington has declined significantly. Sage grouse range has declined to about 8 - 10 % of historic range. Local populations were extirpated as recently as the mid-1980's. Major threats that remain to the two small populations include the potential for catastrophic fire, impacts of military training, impacts of intensive grazing, continued conversion of shrub steppe to cropland or residential development, and the uncertain long term future of the federal Conservation Reserve Program.
For these reasons, the Department recommends that the sage grouse be designated a State Threatened species.
Draft documents are provided for informational purposes only. Drafts may contain factual inaccuracies and may not reflect current WDFW policy.