Habitat Associations and Abundance Trends of the American Kestrel on a Transect in the Southern Sierra Nevada Foothills, California

We used data from 17 years of surveys along a transect in the Sierra Nevada foothills in eastern Merced and western Mariposa counties of California to study differences in winter habitat associations between female and male American Kestrels (Falco sparverius) and to assess trends in abundance over this period. Consistent with findings from other studies, we found that females preferentially occupied the higher quality habitat (grassland). We used year-round data from these surveys to test competing hypotheses to explain this sex-based habitat segregation. Additionally, we found a significant positive trend in kestrel winter abundance over the 17-year duration of these surveys. We discuss possible explanations for this unexpected positive trend.