Characteristics and Dynamics of Greater Sage-Grouse Populations

Early investigations supported the view that Greater Sage-Grouse (Centrocercus urophasianus) population dynamics were typical of other upland game birds. More recently, greater insights into the demographics of Greater Sage-Grouse revealed this species was relatively unique because populations tended to have low winter mortality, relatively high annual survival, and some populations were migratory. We describe the population characteristics of Greater Sage-Grouse and summarize traits that make this grouse one of North America’s most unique bird species. Data on movements, lek attendance, and nests were obtained from available literature, and we summarized female demographic data during the breeding season for the eastern and western portions of the species’ range. Lengthy migrations between distinct seasonal ranges are one of the more distinctive characteristics of Greater Sage-Grouse. These migratory movements (often >20 km) and large annual home ranges (>600 km²) help integrate Greater Sage-Grouse populations across vast landscapes of sagebrush (Artemisia spp.)â€"dominated habitats. Clutch size of Greater Sage-Grouse averages seven to eight eggs and nest success rates average 51% in relatively nonaltered habitats while those in altered habitats average 37%. Adult female Greater Sage-Grouse survival is greater than adult male survival and adults have lower survival than yearlings, but not all estimates of survival rates are directly comparable. The sex ratio of adult Greater Sage-Grouse favors females but reported rates vary considerably. Long-term age ratios (productivity) in the fall have varied from 1.4 to 3.0 juveniles/adult female.