California condors, one of the world's most endangered species, are facing lead poisoning from hunters' bullets "at epidemic levels," and will not recover unless further steps are taken to control it, a new study Monday found.


So far, even a ban on lead bullets in the birds' habitat appears to have had little effect, the study found.

"Lead poisoning is preventing the recovery of California condors," said Myra Finkelstein, a research toxicologist at UC Santa Cruz who was a lead author of the study. "The population is not self-sustaining."

The problem is that condors -- the birds with the largest wingspan in North America -- are scavengers. They eat dead deer, pigs and other animals, often that hunters have shot. They ingest bullet fragments and are poisoned.

Responding to the problem, former California Gov. Arnold Schwarzenegger signed a law in 2007 to ban the use of hunting with lead bullets, slugs or buckshot in the condors' range, which extends from Los Angeles to San Jose, where the birds have been seen atop Mount Hamilton. But it hasn't worked. Birds analyzed before the law took effect had blood levels the same as birds analyzed afterward.



"If just one has a lead bullet fragment, that can be enough to kill the bird," she said.




Although the population growth has been impressive, it is deceptive because it is highly dependent upon human intervention, the researchers said in Monday's study, which was published in the Proceedings of the National Academy of Sciences.


Video: Condors and lead bullets

Video from QUEST on KQED Public Media.


Researchers were surprised, Finkelstein said, by the extensive poisoning.




"I haven't seen the study yet, but there are a lot of people out there who still question the science," said Bill Gaines, president of the California Outdoor Heritage Alliance. "But if the science is accurate we are not going to stand in the way. This is the kind of issue for the Fish and Game Commission, not the Legislature."

In California, the state Department of Fish and Game -- along with some hunting and environmental groups -- has worked to promote the lead ban in condor habitat. Some surveys show high compliance rates. But there is little enforcement, and ranchers or hunters can still use lead bullets and shot, which are cheaper and more readily available than other types of ammunition, such as copper, with little risk of getting caught.


"We've removed toxic lead from gasoline, paint and most products exposing humans to lead poisoning, now it's time to do the same for hunting ammunition to protect America's wildlife," said Jeff Miller, a spokesman for the Center for Biological Diversity.
