Birds of prey suffer Pb poisoning when they ingest Pb shotgun pellets or bullet fragments embedded in the flesh of dead or wounded animals shot with Pb-based ammunition. This source of exposure is responsible for virtually all cases of Pb poisoning in adult raptorial birds. Secondary Pb poisoning of bald eagles (Haliaeetus leucocephalus) that scavenge hunter-shot ducks was a major consideration leading to a national prohibition on the use of Pb shot for waterfowl hunting in the US. A similar phenomenon has also been documented in upland habitats where various eagle, hawk, and owl species that feed on terrestrial prey are documented to have died of Pb poisoning, probably from incidental ingestion of Pb shot lodged in carcasses of the upland game birds and mammals that they feed upon. Although the overall incidence of such poisonings is low for most raptor species, accounting for about 3-6% of total reported mortality, Pb poisoning from ingestion of Pb bullet fragments embedded in carcasses of hunter-killed animals is a major cause of mortality for California condors (Gymnogyps californianus) and has been an important factor limiting the successful reintroduction of this endangered species. Other large scavengers such as bald eagles and vultures that feed on large carrion killed using Pb ammunition are similarly at risk for this sort of Pb exposure and poisoning. Human communities, especially those that rely on subsistence hunting, are also at risk for increased dietary Pb exposure from consumption of game animals killed with Pb-based ammunition whose flesh consequently contains numerous small fragments of metallic Pb.
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