Environmental Contaminants in Tissues of Bald Eagles Sampled in Southwestern Montana, 2006–2008

Abstract Blood and feathers of Bald Eagles (Haliaeetus leucocephalus) banded as nestlings (n  =  17), captured as free-flying (n  =  91), or submitted for rehabilitation (n  =  29) in southwestern Montana between December 2005 and April 2008 were sampled for mercury (Hg), selenium (Se), lead (Pb), seven other trace elements, and organochlorines. Hg concentrations in blood (hereafter “HgB”) did not differ between captured eagles and those submitted for rehabilitation, and HgB in both were higher than concentrations in nestlings (P < 0.01). Se concentrations in blood (“SeB”) were similar among groups. Pb concentrations in blood (“PbB”) were higher in captured eagles than in those submitted for rehabilitation (P  =  0.05). No bird submitted for rehabilitation exhibited toxic levels of PbB, but 9% of captured eagles did. HgB and PbB in captured eagles declined as date of capture advanced from autumn to spring. Hg and Se concentrations in feathers (“HgF”; “SeF”) tended to increase with age-class. HgB and SeB, ...