FALL MIGRATION OF TURKEY VULTURES AND RAPTORS THROUGH THE SOUTHERN SIERRA NEVADA, CALIFORNIA

Abstract

The migration of Turkey Vultures (Cathartes aura) is not nearly as well studied as that of many species of raptors. Raptor migration counts are conducted annually at numerous locations throughout North America (Kerlinger and Gauthreaux 1985, Heintzelman 1986, Kerlinger 1989). Count sites are generally located along mountain ridges or coastlines where migrating raptors congregate (Kerlinger and Gauthreaux 1985, Kerlinger 1989). Both raptors and vultures migrate by day, taking advantage of thermal updrafts. However, sites that provide good conditions for migrating raptors, or for raptor viewing, do not necessarily provide optimal conditions for migrating vultures. Indeed, large flights of migrating vultures (i.e., >5000 individuals) are rarely recorded at hawk-watch sites.