Origins of Lead in Populations of Wild Raptors

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Many wildlife species are threatened by poisoning from anthropogenically derived lead, and routes of lead exposure are unclear.

USGS scientists used blood samples collected between 2012 and 2016 from cohort sibling nestlings of four species of raptors - golden and bald eagles, ferruginous hawks, and osprey - from across North America to test whether these birds are exposed to lead through continuous inhalation or episodic ingestion. Results suggest episodic ingestion, which occurs when raptors consume prey previously contaminated with lead, is a more likely avenue for higher levels of lead than continuous inhalation of airborne lead. This study provides some of the first empirical population-level information on the way these birds are exposed to lead and shows the importance of lead ingestion to avian predators and scavengers.

Katzner, T.E., Stuber, M.J., Slabe, V.A., Anderson, J.T., Cooper, J.L., Rhea, L.L., Millsap, B.A., 2018, Origins of lead in populations of wild raptors: Animal Conservation, v. 21, no. 3, p. 232-240,