RESUMO
In wild waterfowl, poor winter body condition may negatively affect migration, survival, and reproduction. Environmental contaminants have been shown to adversely affect the body condition of captive birds, but few field studies have examined body condition and contaminants in wild birds during the winter. We assessed the body condition of carcasses from a collection of canvasbacks (Aythya valisineria) and lesser (A. affinis) and greater scaup (A. marila) wintering in coastal California. We used Akaike information criterion (AIC) to select the model with the best balance of parsimony and goodness of fit that related indices of body condition with concentrations of Cd, Cu, Hg, Se, and Zn. Total ash-free protein in canvasbacks decreased with increasing Se concentrations, and pancreas mass decreased with increasing Hg. We combined the closely related lesser and greater scaup in analyses and found that total carcass fat, pancreas mass, and carcass mass decreased with increasing Zn concentrations, and pancreas mass decreased with increasing Hg. Our AIC analysis indicated that some indices of body condition in diving ducks were inversely related to some environmental contaminants in this collection, but additional AIC analyses should be conducted across a wider range of contaminant concentrations to corroborate our findings.
