Central Valley winter raptor survey (2007-2010): Winter raptor population estimates

Abstract

We made rough estimates of the populations of various raptors species in the Central Valley and the U.S. and Canda by extrapolating from the densities we observed in various habitats. Our U.S./Canada estimates for most species fell with the range of other published estimates except for the Bald Eagle (Haliaeetus leucocephalus) and Ferruginous Hawk (Buteo regalis), which both had extrapolated estimates larger than those of other authors.