California condors have come back from the brink of extinction. But according to a study released Monday, dangerous levels of lead poisoning could keep the population from fully recovering.
 
In 1982, there were just 22 condors in California. Those few birds went into a breeding program that’s put more than a hundred condors in the wild today in the state. But they still survive with human help.

"It is an enormous amount of effort that goes into keeping these condors out in the wild," says study author Myra Finkelstein of UC Santa Cruz. California condors are captured for blood tests twice a year. "And if the birds are lead poisoned, they get sent to the zoo and treated with clinical therapy," she says.