A record number of 21 endangered California condors were treated at the Los Angeles Zoo and Botanical Gardens for lead poisoning in October — more than half of what the center sees in a typical year, officials reported.
The zoo's announcement comes just weeks after Gov. Jerry Brown signed legislation requiring hunters to use non-lead ammunition in an effort to keep the toxic element from being passed on from carcasses to scavengers, such as condors.
Adam Keats, senior counsel and urban wildlands program director for the Center for Biological Diversity, attributed the high quantity of condor poisonings to hunting.
"There's a wide use of lead ammunition in condor habitats. The availability of lead needs to be reduced by sale and stocking," Keats said.
Lead toxicity is the leading cause of death in juvenile and adult condors, said Curtis Eng, chief veterinarian at the L.A. Zoo and manager of the California Condor Program. He confirmed that one bird had died of lead toxicity earlier this year.
"That's scary to see so many clinically sick birds," he said in a statement.
The Gottlieb Animal Health and Conservation Center at the zoo found that although most of the condors brought in appeared healthy, they had staggering levels of lead in their systems. Low body weight, lack of appetite and signs of crop stasis — when the stomach stops moving food — were listed among the most common symptoms.
The bald-headed birds have wingspans of nearly 10 feet, making them the largest in North America. And because the scavengers subsist on large amounts of carrion, they're particularly susceptible to consuming tainted meat from animals shot with lead ammunition.
By the 1980s, they were nearly driven to extinction, prompting an aggressive preservation plan. As a result, there are now about 231 condors in the wild, according to the Ventana Wildlife Society.