Lead exposure of red-shouldered hawks during the breeding season in the central Appalachians, USA

Lead is toxic to humans and wildlife. Most studies of lead exposure of raptors focus on the winter, non-breeding season when they scavenge heavily. We evaluated blood lead concentrations (BLCs) of red-shouldered hawks (Buteo lineatus) during the non-scavenging season in the eastern United States. BLCs of 53 of 70 hawks were above the limit of detection ( x¯ = 9.25 µg/dL ± 19.81; ± SD). Adult hawks had higher BLCs ( x¯ = 12.86 µg/dL ± 24.72) than did nestlings ( x¯ = 3.25 µg/dL ± 2.62; p ≤ 0.001, χ2 = 13.2). There was no difference in BLCs of adult hawks among physiographic provinces but there were differences between urban and non-urban settings (p = 0.04, χ2 = 4.2). Soils and invertebrate hawk prey also had quantifiable lead concentrations. Our work shows that red-shouldered hawks are exposed to lead when not scavenging, and suggests pathways by which these birds may be exposed.