for National Geographic News
Hunters in California may be unintentionally killing off the state's rare condors.
Lead from shotgun pellets and other ammunition is poisoning many of the vultures as they scavenge abandoned carcasses and gut piles, a new study confirms.
The poisonings are threatening efforts to reestablish wild populations of the scavenger, which nearly died out 20 years ago because of dwindling food supplies and poison traps left by ranchers. (Related photo: "Rare Condors Found Nesting in Redwood" [March 2006].)
The new research compares the types of lead found in condors' blood with the lead from ammunition and from dead wild animals not killed by hunters.
The results, which were published online last week by the journal Environmental Science and Technology, show a match between the lead in acutely poisoned birds and the lead in hunters' bullets.
California condors first began to decline during the Pleistocene era, which ended about 12,000 years ago. The extinction of many large mammals left the vultures with little to eat.
A remnant population survived near the U.S. Pacific coast, where they fed on dead whales and seals that washed ashore.
Whaling and fur hunting further restricted the birds' food supply. Dead livestock from increased ranching provided no relief, as ranchers often intentionally poisoned carcasses to kill predators such as wolves, which also kill the condors.
By 1982 only 22 condors were left, 19 of them in the wild. Four years later 11 of the wild birds had died, prompting a controversial decision to catch the remaining birds and breed them in captivity.
The last wild condor was captured in the spring of 1987.
The condor recovery project has since succeeded in raising a number of chicks to adulthood, but many of the birds don't survive after being released into the wild.
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