In the recent decade, 51% of American Kestrel migration counts across North America suggest stable numbers while 22% of sites show declining counts. The majority of sites that reported kestrel declines are Eastern sites, but kestrel counts also declined at one site in the Central Region, and four sites in the West. Cape May, New Jersey, observed the highest seasonal average at 4,901 migrants. The increasing and stable trends in this analysis appears to be a recent occurrence, given widespread concern about this species based on past declines in migration count trends. Migration count results from 1999-2019 and 1989-2009 indicate much broader declines, with 59% of sites declining.

Winter survey data from the Christmas Bird Count (CBC) also show declining 10-year trends continent-wide with the annual percent change in population reported to be -0.81% from 2009-2021. Lastly, the relative abundance of American Kestrels throughout North America seems to be declining, as reflected by eBird trend data from 2012-2022. The eBird data reports an annual decline in abundance of -22.5% for all of North America, but with some localized increases, such as in New Brunswick (19.9% increase). A 2023 publication by Oleyar et al. evaluated long-term kestrel population trends and found widespread declines. In both the central and eastern regions of North America, kestrel counts declined during the fall and winter over the last 20- and 30-year periods. Declines were also observed in western North America, but these declines were explained by increasing wintering counts in northern regions. This suggests a change in migratory tendencies, such as migrating shorter distances or kestrels electing not to migrate (Oleyar et al. 2023).

There are many ongoing research efforts to understand the cause for widespread long-term declines in this species. The American Kestrel is listed as a Species of Least Concern globally by the IUCN Red List, but is listed as a Species of Concern in 21 State Wildlife Action Plans and are listed as a Bird of Conservation Concern by the USFWS (McClure et al 2021, U.S. Fish and Wildlife Service 2021). Pesticides and other environmental contaminants associated with agriculture, along with habitat loss and cavity competitors are some proposed major threats to the species.

Citations

McClure, C., Brown, J., Schulwitz, S., Smallwood, J., Farley, K., Therrien, J.-F., Karl, M., Karen, S., & Julie, H. (2021). Demography of a widespread raptor across disparate regions. Ibis.

Oleyar, D., Goodrich, L. J., Ethier, D., Brandes, D., Smith, R., Brown, J., & Sodergren, J. (2023). Thirty years of migration and winter count data indicate regional differences in population trajectories for american kestrels in north america. Journal of Raptor Research, 57(2). https://doi.org/10.3356/JRR-22-17

U.S. Fish and Wildlife Service. (2021). Birds of Conservation Concern 2021. United

States Department of the Interior, U.S. Fish and Wildlife Service, Migratory Birds, Falls Church,

Virginia. http://www.fws.gov/birds/management/managed-species/birds-of-conservation-concern.php