And while we're on the topic of lead poisoning

Note: I was going to not publish this, but it is different from the post that  Baldr put up--so here goes!

 It seems that the endangered California Condor is threatened by lead poisoning.
The California condor, which once numbered in the thousands in the western United States and Mexico, is the largest land bird in North America. Attempts at reintroduction since the bird's near extinction in 1982 have led to free-flying populations in Arizona, California and Baja California. Dubbed "thunderbird" by American Indians, its impressive wings can span more than 9 feet. A type of vulture, the creature's bald head allows feeding without the mess of carcass flesh sticking to its plumage.

The Condor is endangered by lead exposure from ammunition and requires ongoing human intervention for population stability and growth, according to a new study led by the University of California, Santa Cruz, and involving the University of Colorado Boulder.

Since 1982, the condor population has increased from 22 to approximately 400, but only through intensive management including captive breeding, monitoring and veterinary care. The bird's recovery has been deceptively successful as its primary threat -- poisoning from lead-based bullets ingested as fragments from carrion -- has gone largely unmitigated, according to the study. Twenty percent of condors captured every year have deadly levels of lead. Scientists said they were surprised at the high numbers, but a condor eats between 75 and 150 dead animals a year and one lead fragment is enough to kill it.
A study, published in Proceedings of the National Academy of Sciences, shows that annually from 1997 to 2010, 20 percent of the California condors sampled suffered lead poisoning and needed chelation therapy, a metal detoxification process that also is used for children with lead poisoning. Cumulatively over the time period, nearly half of the population tested was poisoned by lead, with many birds suffering repeat poisoning within and across years.

"Lead exposure and poisoning levels in condors continue to be epidemic," said co-author Dan Doak, a new endowed chair and professor in CU-Boulder's Environmental Studies Program. "Despite the current efforts to help the species, the wild population will decline again toward extinction in a few decades unless these unsustainable and very expensive efforts continue in perpetuity."

From 1997 to 2010, the annual prevalence of lead exposure -- with blood lead levels indicating potentially serious but nonlethal effects -- ranged from 50 to 88 percent in California condors in the wild. Also, the annual median blood lead levels in free-flying California condors exceeded the average for pre-release condors bred in captivity by at least threefold.

The researchers found no evidence that California's having outlawed lead shot in key areas inhabited by condors in 2008, resulted in lower incidence of lead exposure and poisoning. Although alternatives to lead-based bullets are available, regulations limiting the use of lead-based ammunition face stiff opposition from hunting organizations and gun-rights groups, according to the researchers.

The National Rifle Association regards any attempts to limit the use of lead in ammunition—for instance, using substitutes like copper—as an anti-gun move to infringe on gun owners’ constitutional rights.

To Learn More:

• California Condors Face “Epidemic” Lead Poisoning, Finds Study (by Stephanie Powers, Christian Science Monitor)
• Lead Poisoning and the Deceptive Recovery of the Critically Endangered California Condor (Proceedings of the National Academy of Sciences)
• Bullet Fragments Killing Condors (by Ker Than, Live Science)
• New Study: Lead Poisoning of Condors at “Epidemic Proportions” (by Paul Rogers, Mercury News)
• EPA Sued over Wildlife Exposure to Spent Ammo Lead (by Laura Zuckerman, Reuters)
• California Condors Face Lead Menace (by Meera Subramanian, Nature)