Great Basin Naturalist


We studied summer habitat use by Columbian Sharp-tailed Grouse (Tympanuchus phasianellus columbianus) in western Idaho during 1983–85. Vegetative and topographic measurements were recorded at 716 locations of 15 radio-tagged grouse and at 180 random sites within the major vegetation/cover types in the study area. The mean size of summer home ranges was 1.87 ± 1.14 km2. Of eight cover types identified in the study area, individual grouse used the big sagebrush Artemisia tridentata) cover type more than or in proportion to availability, the low sagebrush (A. arbuscula) in proportion to availability, and avoided the shrubby eriogonum (Eriogonum spp.) type. Characteristics of the big sagebrush cover type that Sharp-tailed Grouse preferred include moderate vegetative cover, high plant species diversity, and high structural diversity. Grouse used areas of dense cover (i.e., mountain shrub and riparian cover types) primarily for escape cover. Compared with random sites, grouse selected areas with (1) greater horizontal and vertical cover, (2) greater canopy coverage of forbs typically decreased by livestock grazing, (3) greater density and canopy coverage of arrowleaf balsamroot (Balsamorhiza sagittata), and (4) greater canopy coverage of bluebunch wheatgrass (Agropyron spicatum) in the big sagebrush cover type in 1984 and the low sagebrush cover type in 1985. The importance of the native perennials arrowleaf balsamroot and bluebunch wheatgrass became apparent during a drought year when many exotic annuals dried up and provided no cover. Overall, grouse selected vegetative communities that were least modified by livestock grazing.