Brood Habitats of Sympatric Sage Grouse and Columbian Sharp-Tailed Grouse in Wyoming

Abstract

Habitats used by sympatric sage grouse (Centrocercus urophasianus) and Columbian sharp-tailed grouse (Tympanuchus phasianellus columbianus) were compared. Sage grouse broods occurred most often (68%) in sagebrush (Artemisia spp.)-grass and sagebrush-bitterbrush (Purshia tridentata) habitats, whereas sharp-tailed grouse broods occurred most often (73%) in mountain shrub and sagebrush-snowberry (Symphoricarpos oreophilus) habitats. Mountain shrub and sagebrush-snowberry habitats were used by sharptailed grouse more (P < 0.05) than expected based on their availability. Broods of both species used areas within each habitat with less shrub cover than average for that habitat. Sharp-tailed grouse broods were associated with mountain snowberry, oniongrass (Melica spp.), and sulphur buckwheat (Eriogonum umbellatum). Sites used by sage grouse contained needle-and-thread (Stipa comata) and desert alyssum (Alyssum desertorum). J. WILDL. MANAGE. 54(1):84-88 Distribution of sage grouse and Columbian sharp-tailed grouse historically overlapped in 8 western states (Aldrich 1963). The geographic range of both species has been reduced, and Columbian sharp-tailed grouse currently occupy <10% of their former range (Miller and Graul 1980). Presently, Columbian sharp-tailed grouse occur only in Idaho, Wyoming, Utah, Colorado, Montana, Washington, and British Columbia (Miller and Graul 1980). Although habitat use patterns have been documented for sage grouse (Dalke et al. 1963, Klebenow 1969, Rothenmaier 1979) and sharp-tailed grouse (Rogers 1969, Oedekoven 1985, Marks and Marks 1987) independently, habitat use has not been investigated for the 2 species when they occur sympatrically. Both species occupy shrub-steppe communities (Dalke et al. 1963, Marks and Marks 1987) dominated by sagebrush and other shrubs including rabbitbrush (Chrysothamnus spp.), antelope bitterbrush, and common chokecherry (Prunus virginiana). The objectives of our study were to document vegetation types used by sage and sharp-tailed grouse broods and to examine whether sites used by the 2 species differed structurally or vegetatively. Funding was provided by the Rawlins District of the Bureau of Land Management. We gratefully acknowledge L. J. Saslaw and J. R. Farrell of the Bureau of Land Management and D. L. Moody of the Wyoming Game and Fish Department for assistance in locating grouse leks. S. P. Gallagher and A. L. Vail-Klott assisted with vegetation sampling and locating grouse broods. We thank W. R. Eddleman for comments on early drafts of the manuscript. This study was conducted under the auspices of the Wyoming Cooperative Fishery and Wildlife Research Unit, U.S. Fish and Wildlife Service, University of Wyoming, Wyoming Game and Fish Department, and Wildlife Management Institute cooperating.