Eagles and vultures are exposed to high levels of lead in Canada

Raptors and corvids accidentally ingest spent lead ammunition while scavenging on remains of hunted game, resulting in acute and chronic toxicological effects. To evaluate lead exposure of scavenging birds across Canada, we initiated a national study in 2018 to (1) assess lead concentrations in raptors and corvids, (2) identify bird species and regions at higher risk, and (3) examine antimony (a hardener in lead ammunition alloys) as a co-contaminant in lead-exposed birds for potential evidence of associations with lead ammunition. Through a multi-agency collaboration, 954 livers were obtained from dead and moribund birds brought to wildlife organizations between the years 2000 and 2024. Supplementing sample measurements with previously published data, a total of 1097 liver lead concentrations were compared to an established toxicity threshold of 20 µg/g dry weight associated with a high risk of clinical lead poisoning. Raptors showed a greater frequency of lead exposure than corvids, particularly Bald Eagles, Golden Eagles, and Turkey Vultures. Approximately 1 in 8 Bald Eagles found dead had high lead concentrations consistent with poisoning, though seasonal and geographic variation was observed. Bird livers with high lead concentrations also had detectable antimony, consistent with ingestion of lead ammunition alloys. Currently, scavenging birds are vulnerable to lead exposure in Canada.