Sen. John McCain (R-Ariz.) wants the Fish and Wildlife Service to encourage hunters to use ammunition that does not contain lead.

Getting hunters to use different types of bullets on their own accord is the best way to make sure that California condors are protected from being poisoned by the metal, he said in a statement on Tuesday.

Lead poisoning is a major hazard to the endangered birds, and the cause of about half of all their deaths in the wild.

The birds can accidentally eat fragments of lead bullets when they feast on the carcasses of dead animals shot by hunters.

In his statement, McCain said that the federal government should adopt a strategy to get hunters to voluntarily stop using lead bullets, as Arizona and Utah have done, and promote other types instead.