Description

Greater sage-grouse are the largest grouse in North America. Males can weigh from four to seven pounds and hens weigh in at two to four pounds. Both males and females have dark grayish-brown body plumage with many small gray and white speckles, and their long pointed tail is approximately half the length of their body. Adult males are distinguished by blackish-brown throat feathers which are separated by a white V-shaped ruff around the neck. White breast feathers conceal two large skin sacs (used in courtship displays) which are yellow-green in color. Males also have yellow eyecombs, obvious in the spring during courtship displays. Immature birds can be distinguished from adults by their light yellowish-green toes (adults have dark green toes). 

Sage-grouse are known for their courtship displays during the spring breeding season.  Male sage-grouse gather together on areas of bare soil, short grass, or other exposed earth called leks.  One lek can hold up to several hundred sage-grouse.  Males defend their territory on a lek to establish dominance and lure a mate by strutting and vocalizing.

After mating, females travel to nesting sites where they incubate eggs and rear the chicks alone.  Sage-grouse lay six to nine eggs.  Forbs (herbaceous flowering plants that are not grass) and insects are essential parts of the diet of sage-grouse chicks.  Adults eat insects but survive on sagebrush throughout the winter.  Sage-grouse typically live three to six years.  Juvenile survival, depending on food availability, habitat, predation, and weather, ranges from 7 to 60 percent of juveniles surviving to the first breeding season.

Range

Sage-grouse are native to North America.  Before the 19th century, sage-grouse inhabited the following 13 states and 3 Canadian provinces: Washington, Oregon, California, Nevada, Idaho, Montana, Wyoming, Colorado, Utah, South Dakota, North Dakota, Nebraska, Arizona, British Columbia, Alberta, and Saskatchewan.  Sage-grouse are believed to now be extinct in Nebraska, British Columbia, and Arizona.  Historical populations of sage-grouse are estimated as high as 1.6 million to 16 million individuals.  The current population of sage-grouse is uncertain, but in 2000 we estimated there were between 100,000 and 500,000 birds range-wide.  Oregon is one of six states with larger (> 20,000) estimated numbers of birds compared to other areas.  The range of sage-grouse in Oregon includes the following counties: Baker, Crook, Deschutes, Grant, Harney, Klamath, Lake, Malheur, Union, and Wheeler.

Habitat

Greater sage-grouse depend on a variety of shrub-steppe habitats throughout their life cycle, and are dependent on several species of sagebrush for their survival. Large areas continuously covered with sagebrush are crucial habitat for sage-grouse.  Sagebrush provides cover for nesting sage-grouse and food throughout the winter.  Sage-grouse habitat also must consist of lek sites for male courtship displays.  Sage-grouse are attached to particular habitat sites and will use the same areas for breeding, nesting, brood rearing, and wintering repetitively, even if the area loses its viability. Sagebrush is widespread in the intermountain lowlands of the western United States, but is an ecosystem that is highly threatened throughout North America. 

Reason for Decline

Historically, sage-grouse decline was caused by a combination of overhunting, habitat loss, degradation, and fragmentation.  Prior to European settlement, Oregon had 17.7 million acres (7.2 million hectares) of sage-grouse habitat.  Twenty-one percent of this habitat has been lost, and the remaining habitat is fragmented due to natural and artificial factors. Sage-grouse cannot survive in areas where sagebrush no longer exists, and a sagebrush community may take years to recover from disturbance and some range management practices.

Currently, human disturbance has an impact on sage-grouse due to direct habitat loss and fragmentation resulting from wildfire, invasive species (e.g., cheatgrass, juniper, and noxious weeds), energy development, urbanization, agricultural conversion, intensive grazing, and infrastructure development. Grazing by livestock is the most common form of land use in sage-grouse habitat. However, the effects of grazing on sage-grouse habitat vary widely with the timing and intensity of use and various environmental factors. Light-to-moderate levels of grazing can have a positive or neutral impact on sage-grouse habitat, meaning this land use can be compatible with healthy sage-grouse habitat.

Conservation Measures

In the 1920s and 1930s, various state wildlife agencies, concerned about the effect of hunting on the sage-grouse population, either closed hunting seasons on the species or highly reduced bag limits and season lengths.  In Oregon, harvest does not exceed five percent of the projected fall population in an effort to avoid any measurable impact to the size of the breeding population.

The Oregon Department of Fish and Wildlife, in cooperation with other land managers and private individuals, developed a sage-grouse conservation plan for Oregon.  The plan seeks to maintain sage-grouse habitat by outlining and implementing voluntary conservation measures that reduce negative impacts that can result from wildfire, invasive species, and a variety of land use practices.  Current conservation measures mainly focus on maintaining and improving the remaining sagebrush habitat, primarily by removing invasive plants. The plan also includes a landscape approach to sage-grouse habitat protection, referred to as core areas. This approach identifies important sage-grouse habitat based on the location and density of breeding birds and associated habitat, as well as connectivity corridors that support other seasonal uses. Core areas are a planning tool to help identify appropriate mitigation in the event of human development in sage-grouse habitat.

The Fish and Wildlife Service joined with the Western Association of Fish and Wildlife Agencies, representing all of the western state wildlife agencies and several other federal agencies, in 2006, to develop the Greater Sage-Grouse Comprehensive Conservation Strategy. The release of this strategy marked a shift from conservation planning to conservation implementation, incorporating adaptive management principles to inform and guide future management practices. The Fish and Wildlife Service has also worked closely with the NRCS in developing conservation opportunities on private lands through their sage-grouse initiative. In addition, we are pursuing the opportunity to develop Candidate Conservation Agreements for a variety of management activities in order to maintain or improve sage-grouse habitat in Oregon.

References

Hagen, C. April 22, 2011. Greater Sage-Grouse Conservation Assessment and Strategy for Oregon: A Plan to Maintain and Enhance Populations and Habitat. Oregon Department of Fish and Wildlife. 207 pp.

Oregon Department of Fish and Wildlife. Sage-Grouse Webpage. http://www.dfw.state.or.us/wildlife/ sagegrouse/

U.S. Fish and Wildlife Service. Region 6 Sage-Grouse Webpage. http://www.fws.gov/mountain-prairie/species/birds/sagegrouse/

U.S. Fish and Wildlife Service. March 23, 2010. 12-Month Findings for Petitions to List the Greater Sage-Grouse (Centrocercus urophasianus) as Threatened or Endangered. 75 FR 13910.

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