Morphological changes in American kestrels (Falco sparverius) at continental migration sites

Autor: Teresa E. Ely, Christopher W. Briggs, Shawn E. Hawks, Gregory S. Kaltenecker, David L. Evans, Frank J. Nicoletti, Jean-François Therrien, Olin Allen, John P. DeLong
Jazyk: angličtina
Rok vydání: 2018
Předmět:
Zdroj: Global Ecology and Conservation, Vol 15, Iss , Pp - (2018)
Druh dokumentu: article
ISSN: 2351-9894
DOI: 10.1016/j.gecco.2018.e00400
Popis: Many American kestrel (Falco sparverius) populations are declining across North America. Potential causes include mortality from reduction in food availability, a changing climate, habitat degradation, an increase in avian predators, disease, and toxins. We analyzed American kestrel count and banding data from seven raptor migration sites throughout North America with at least 20 years of migration data. We used count data to determine the year at which the kestrel population began a significant decline and then used banding records to determine whether body mass and wing chord declined after this point. We found reductions in kestrel body mass at three sites and reductions in kestrel wing chord at five sites. Our results indicate declines in body size at the majority of sites are consistent with the hypotheses that food availability, impacts of a changing climate, or predation risk may be contributing to population declines. Keywords: Body size, Falcon, Mass, Population decline, Raptor, Wing chord
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