Great Basin Naturalist


Seventy-four species of montane breeding birds were evaluated for their vulnerability to extirpation in the Great Basin. Although none of these species are endemic to the Great Basin, the montane island system results in a unique pattern of species associations. Loss of species from these montane communities could be indicative of region wide habitat degradation. I ranked susceptibility to extirpation based on seven biological variables: geographic range, population size, reproductive potential, susceptibility to cowbird parasitism, migratory status, and diet specialization. Each variable was weighted equally in its contribution to vulnerability, and scores were the sum of trait scores for each species. Different suites of life-history traits led to similar vulnerabilities. The following 10 montane bird species were categorized as most vulnerable to extirpation from the Great Basin, listed as most to least vulnerable: Olive-sided Flycatcher (Contopus borealis), Painted Redstart (Myioborus pictus), Hammond's Flycatcher (Empidonax hammondii), Veery (Catharus fuscescens), Whip-poor-will (Caprimulgus vociferus), Lincoln's Sparrow (Melospiza lincolnii), Black-backed woodpecker (Picoides arcicus), Three-toed Woodpecker (P. tridactylus), Himalayan Snowcock (Tetraogallus himalayensis), and Nashville Warbler (Verminvora ruficapilla). Species of similar vulnerability scores often were dissimilar in threats related to their vulnerability. No taxonomic patterns in vulnerability were found. This type of analysis should be used proactively to identify vulnerable species or populations and to set priorities for research management.