http://green.blogs.nytimes.com/2012/03/15/zeroing-in-on-lead-in-hunters-bullets/

A California condor soars over the hills of Big Sur after being treated for lead
poisoning and re-released.

Citing risks to birds and to human health, roughly 100 environmental groups
formally asked the federal Environmental Protection Agency this week to ban or
at least impose limits on lead in the manufacturing of bullets and shotgun
pellets for hunting or recreation.

The use of such ammo by hunters puts about 3,000 tons of lead into the
environment annually and causes the death of 20 million birds each year from
lead poisoning, said Jeff Miller, a conservation advocate at one of the groups,
the Center for Biological Diversity.

One of the species most at risk from lead is the endangered California condor, a
scavenger that may ingest lead while eating the remains of animals shot with
lead bullets, federal and state wildlife and park officials say. The lead
pellets within shotgun shells also closely resemble “grit,” pebbles consumed by
many species of birds that are necessary for digestion.