Identification of Columbian Sharp-Tailed Grouse Lek Sites in South Central Wyoming

Abstract

The Columbian Sharp-tailed Grouse (Tympanuchus phasianellus columbianus; hereafter CSTG) occupies approximately 10% of its historic range and is a species of conservation concern in 7 U.S. states and British Columbia. Because little is known about the status of CSTG in Wyoming, we sought to model the relative probability of lek site occurrence within the known distribution of CSTG in the state to identify areas that contained previously undocumented lek sites. The proximity of nesting and brood-rearing habitats to leks advocates their use as a focus of conservation for prairie grouse, including CSTG. We modeled a resource selection function (RSF) to identify areas that were predicted to have a high probability of lek occurrence. In areas identified by the RSF, we searched for leks by conducting ground surveys and surveys from a fixed-wing airplane using aerial infrared (AIR) technology. We identified 6 previously undocumented CSTG leks through ground searches and 4 previously undocumented Greater Sage-Grouse (Centrocercus urophasianus) leks through AIR searches. Newly identified leks represented a 22% increase in the number of known CSTG leks in south central Wyoming. Our method not only improved knowledge of CSTG status in Wyoming, but may also improve identification of unknown lek sites and conservation of lekking habitat and additional reproductive habitats for prairie grouse species in other western states and provinces.