Origins of lead in populations of raptors

Although poisoning from anthropogenically derived lead threatens wildlife of many species, routes of lead exposure are unclear and rarely empirically tested. We used blood lead concentration and isotope ratio (²⁰⁷Pb/²⁰⁶Pb) data from populations of four species of raptors from across North America to test hypotheses associated with lead exposure via inhalation versus ingestion. Mean variation in blood lead concentration among cohort siblings was non‐zero at nests of ferruginous hawks Buteo regalis and osprey Pandion haliaetus (P