Changes in the Growth, but Not the Survival, of American Kestrels (Falco sparverius) Exposed to Environmentally Relevant Polybrominated Diphenyl Ethers

Abstract

Polybrominated diphenyl ether (PBDEs) concentrations are increasing exponentially in biota. We studied the growth of American kestrel (Falco sparverius) nestlings exposed in ovo and during development to environmentally relevant PBDE congeners and concentrations. Eggs within each clutch, divided between groups by laying sequence, were injected into the air cell at 19 days of incubation with safflower oil or penta-BDE congeners BDE-47, -99, -100, and -153 dissolved in safflower oil (18.7 μg total [Σ] PBDEs/egg), approximating current levels in Great Lakes herring gulls. The measured proportions of BDE congeners found in the dosing oil were 56.4% of BDE-47; 27.2% of BDE-99; 24.8% of BDE-100; and 0.6% of BDE-153. For 29 days, nestlings were orally gavaged daily with the same ΣPBDE mixture (15.6 ± 0.3 ng/g body weight/day). Relative congener abundances in the dosing mixture compared to the carcasses suggest biotransformation of BDE-47; BDE-183 was also detected. PBDE exposure did not affect hatching or fledging success. PBDE-exposed nestlings were larger (weight, bones, feathers) as they gained weight more quickly and ate more food, the latter in association with their ΣPBDE body burdens. BDE-100 was most influential on nestling growth, being positively associated with size, weight gain, and food consumption. Increasing concentrations of BDE-183 and -153 were related to longer bones, and BDE-99 to longer feathers. The larger size of the PBDE-exposed birds may be detrimental to their bone structure and have excessive energetic costs. The repeated relationships with BDE-100 and growth may be important for wild Falconidae, since this is the predominant penta-BDE congener in these raptors.

We thank Heather Stapleton of the Chesapeake Biological Laboratory at the University of Maryland Center for Environmental Science for her advice and information regarding possible dosing concentrations used in this study. Conor McKenna and Vanessa Roy were extremely dedicated in handling the birds and various matters during the study at the Avian Science and Conservation Centre of McGill University (Montreal, PQ, Canada). We thank Wouter Gebbink for performing the chemical analyses of PBDEs (GLIER). The research was supported in part by the Great Lakes Program of Environment Canada (K. J. Fernie, J. L. Shutt), as well as a Premier's Research Excellence Award (PREA) and the Canada Research Chairs (CRC) Program (to R. J. Letcher).

Notes

^a The number of birds in which the BDE congener was detected.

^a Significant difference from control (p < .1).