Thirty-one years and $60 million later, the state’s captive breeding program has brought the bird’s population to 424, more than half living in the wild. Yet the main cause of death and illness for the condors remains the same: lead poisoning from ammunition in felled game and “gut piles” left behind by hunters who clean the carcasses in the field.
Today there is little doubt that lead is the primary threat, according to scientists, advocates and conservationists, because captive-bred birds are equipped with radio transmitters, captured and tested annually. The National Rifle Association remains one of the few major groups to deny the connection.
To break the cycle, Gov. Jerry Brown (D) this month signed a ban on lead in hunting ammunition, making California the first state with such a law and settling a dispute that had been fought for decades. The ban will be phased in from 2015 to 2019.
“This is the last major source of lead that we knowingly discharge into the environment,” said Jeff Miller, conservation advocate for the Center for Biological Diversity, which campaigned hard for the new law. “We got it out of gasoline, we got it out of paint, we got it out of toys.”
Hunters have been using lead ammunition for centuries. But the metal is softer than alternatives such as copper alloys and steel, and it fragments easily, leaving particles in animal tissue that scavengers consume.
Lead’s toxicity to humans and animals is well established, and its danger to scavengers has been known since the first article on the subject was published in 1889, according to John McCamman, California-condor coordinator for the U.S. Fish and Wildlife Service.
A 2012 study by a team at the University of California at Santa Cruz found that 30 percent of blood samples taken from condors each year showed levels of lead high enough to cause significant health problems and that 20 percent of the free-flying birds required treatment to remove lead. From 1992 to 2012, the cause of death was established for 123 condors in California, Arizona and Baja California, Mexico; lead was responsible for 42 of the mortalities, according to a 2013 review of the condor’s progress by the Fish and Wildlife Service.
“Lead-based ammunition is the [principal] source of lead poisoning in condors,” the UC-Santa Cruz researchers wrote, adding that “the only hope of achieving true recovery [is] dependent on the elimination or substantial reduction of lead poisoning rates.”
Though there are no similar data for humans, California Assemblyman Anthony Rendon (D) said he sponsored the bill that resulted in the ban because he saw the issue as a public health concern. Rendon said he is worried about hunters and others who might eat meat from deer and other game killed with lead ammunition.