Seasonal Movements of Sage Grouse in Southeastern Idaho

We studied seasonal movements of sage grouse (Centrocercus urophasianus) on, and adjacent to, the Idaho National Engineering Laboratory (INEL) in southeastern Idaho from summer 1977 through fall 1983. The study area included a mountain valley and sagebrush (Artemisia spp.) lowlands. Sage grouse used contiguous areas for wintering and breeding but moved as far as 82 km from winter and breeding areas to summer range. Juvenile sage grouse (n = 32) moved a mean distance of 14.9 km from summer to winter ranges and adult grouse (n = 33) moved a mean distance of 11.3 km. Male sage grouse from the mountainvalley population moved farther to summer range than did mountain-valley females and both sexes from lowland populations (P < 0.05). Movements by male and female sage grouse during fall were generally slow and meandering. Movements by females during spring were also slow and meandering compared to the relatively rapid and direct movements by males. Distances moved were not entirely influenced by the proximity of seasonal habitats, suggesting that seasonal movements tend to be traditional. Sage grouse populations should be defined on a temporal and geographic basis. Protection of sagebrush habitats within a 3.2 km radius of leks may not be sufficient to ensure the protection of year-long habitat requirements. J. WILDL. MANAGE. 52(1):116-122 Sage grouse occupy seasonal habitats, using mesic areas during summer (Klebenow 1969, Wallestad 1971) and sagebrush habitats during winter (Eng and Schladweiler 1972, Beck 1977, Remington and Braun 1985). Grouse occupying sagebrush habitats at relatively low elevation are sometimes nonmigratory (Wallestad 1975), and sage grouse inhabiting mountain valleys or areas with distinct elevational gradients are often migratory (Dalke et al. 1960, Connelly 1982). However, information on the timing and distance of seasonal movements and the spatial relationships of seasonal ranges to migration routes and breeding complexes is often lacking. Only Dalke et al. (1963) and Berry and Eng (1985) attempted to delineate these relationships. This information is necessary for defining sage grouse populations, identifying population habitats, and evaluating impacts of land use changes on this species; thus, allowing meaningful management practices to be implemented. The INEL and adjacent lands in southeastern Idaho contain mountain-valley and sagebrushlowland areas that differ in topography and precipitation (Connelly 1982, Gates 1983). Recognizing these differences, we hypothesized that seasonal movements of sage grouse occupying these areas might differ. Thus, we compared seasonal ranges and movement patterns of sage grouse using separate breeding ranges in mountain-valley and lowland areas. Our objectives were to (1) describe sage grouse seasonal movements; (2) define sage grouse seasonal ranges with respect to each other and to breeding complexes, and migration routes in both mountainvalley and lowland areas; and (3) suggest an approach to defining migratory sage grouse populations. This study was supported by the Office of Health and Environmental Research, U.S. Department of Energy. Technical assistance was supplied by the Idaho Department of Fish and Game, the U.S. Fish and Wildlife Service, and the Bureau of Land Management. We thank all of the individuals from the above agencies who contributed to this effort. We are especially grateful to O. D. Markham and W. J. Arthur for administrative guidance, advice, and field assistance. Field assistance was also provided by D. K. Halford and J. C. Hoag during various portions of this study. Earlier drafts of this manuscript were reviewed by R. E. Autenrieth, I. J. Ball, W. B. Sidle, L. D. Flake, and R. L. Present address: Idaho Department of Fish and Game, 5205 South 5th Avenue, Pocatello, ID 83204. 2 Present address: Cooperative Wildlife Research Laboratory, Southern Illinois University, Carbondale, IL 62901.