Breeding strategy and organochlorine contamination of eggs in lesser scaup (Aythya affinis)

We explored relationships between breeding strategy and contaminant importation and depuration into lesser scaup (Aythya affinis) eggs. Our primary hypothesis was that females accumulate organochlorine (OC) contaminants in lipid reserves obtained on wintering and spring staging areas and depurate those contaminants into eggs on the breeding area proportional to the amount of endogenous reserves used for egg formation. Egg collection occurred at Red Rock Lakes National Wildlife Refuge, Montana, in 2006 for contaminant and stable isotope analysis. Eggs were assayed for 22 lipophilic OCs and endogenous lipid reserves for each egg were estimated using carbon (δ(13)C) stable isotope values. Of the 22 OC analytes tested for, only p,p'-DDE was detected in all samples, oxychlordane was detected in 56%, and no other OC analytes tested for were detected in >50% of samples. The mean percent contribution of endogenous reserves to egg lipids in scaup was 37.9 ± 0.05%, ranging from 0-88.2%. We found little support for the hypothesized relationship between breeding strategy and egg contaminant levels. No significant trend was observed for endogenous reserves and egg contaminant levels of p,p'-DDE or oxychlordane (R (2) < 0.01, P = 0.792; R (2) < 0.01, P = 0.674, respectively). Thus, our results did not indicate that breeding females are importing contaminants from wintering or spring staging areas and depurating those contaminants into their clutches.