Continuing Impacts of West Nile Virus on Birds of California’s Central Valley

Abstract

Using data from Christmas Bird Counts and local epidemiological data, I examined correlations between West Nile virus (WNV) activity and wintering populations of some WNV-sensitive bird species in the Central Valley. Two corvid species, the California Scrub-Jay (Aphelocoma californica) and American Crow (Corvus brachyrhynchos) appear have become resistant to the WNV in the years following the initial outbreak, two other species, the Yellow-billed Magpie (Pica nuttalli) and Loggerhead Shrike (Lanius ludovicianus) continue to show population declines coincident with increased in WNV activity.