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Feeding ecology drives lead exposure of facultative and obligate avian scavengers in the eastern United States

February 5, 2020

Lead poisoning of scavenging birds is a global issue. However, the drivers of lead exposure of avian scavengers have been understood from the perspective of individual species, not cross‐taxa assemblages. We analyzed blood (n = 285) and liver (n = 226) lead concentrations of 5 facultative (American crows [Corvus brachyrhynchos], bald eagles [Haliaeetus leucocephalus], golden eagles [Aquila chrysaetos], red‐shouldered hawks [Buteo lineatus], and red‐tailed hawks [Buteo jamaicensis]) and 2 obligate (black vultures [Coragyps atratus] and turkey vultures [Cathartes aura] avian scavenger species to identify lead exposure patterns. Species and age were significant (α < 0.05) predictors of blood lead exposure of facultative scavengers; species, but not age, was a significant predictor of their liver lead exposure. We detected temporal variations in lead concentrations of facultative scavengers (blood: median = 4.41 µg/dL in spring and summer vs 13.08 µg/dL in autumn and winter; p = <0.001; liver: 0.32 ppm in spring and summer vs median = 4.25 ppm in autumn and winter; p = <0.001). At the species level, we detected between‐period differences in blood lead concentrations of bald eagles (p = 0.01) and red‐shouldered hawks during the winter (p = 0.001). During summer, obligate scavengers had higher liver lead concentrations than did facultative scavengers (median = 1.76 ppm vs 0.22 ppm; p = <0.001). These data suggest that the feeding ecology of avian scavengers is a determinant of the degree to which they are lead exposed, and they highlight the importance of dietary and behavioral variation in determining lead exposure. 

Publication Year 2020
Title Feeding ecology drives lead exposure of facultative and obligate avian scavengers in the eastern United States
DOI 10.1002/etc.4680
Authors Vincent Slabe, James T. Anderson, Jeff L Cooper, Tricia A. Miller, Bracken Brown, Anna Wrona, Patricia Ortiz, John Buchweitz, David McRuer, Ernesto Dominguez-Villegas, Shannon Behmke, Todd E. Katzner
Publication Type Article
Publication Subtype Journal Article
Series Title Environmental Toxicology and Chemistry
Index ID 70216658
Record Source USGS Publications Warehouse
USGS Organization Forest and Rangeland Ecosystem Science Center