The prevalence of lead shot ingestion in wild mallards (Anas platyrhynchos) in the Netherlands.

During the hunting season 1986-1987, 2859 gizzards from mallards shot in the Netherlands were collected. Gizzards were selected radiographically and examined visually for ingested lead shot. The 95% confidence interval of the prevalence of lead shot ingestion was calculated to be 1.7 to 2.9%. In some gizzards a large number of lead shot (12-16) were seen. This is an indication for locally heavily contaminated areas. Especially places where mallards are attracted for hunting purposes, by daily feeding of corn, predispose these birds to lead poisoning. A ban with regard to these hunting practices will probably drastically reduce the prevalence of lead shot ingestion. A change from lead shot to steel shot will solve the problem completely.