The California condor went from being nearly extinct in the 1980s, to having a strong recovery today.
But new research has exposed a new threat to the population, and it has to do with contamination of sea lions, the birds' food source.
Carolyn Kurle is an assistant professor of ecology at UC San Diego. She's also one of the authors of this new research.
"California condors up in Big Sur that are foraging on the coast frequently come into contact with California sea lion carcasses, and other marine mammals but primarily sea lions, and the sea lions are actually contaminated with several types of contaminants," including DDEs, which is a metabolite of the pesticide DDT, Kurle said. When the condors eat from these carcasses, the contamination weakens their offsprings' egg shells.
Joe Burnett, senior biologist with the Big Sur Condor Project at the Ventana Wildlife Society said this impacts birth rates.
"The coastal flock is just one-third of the entire wild flock in California, because you also have birds free-flying birds down in Southern California. So as an overall flock and their reproductive success, it's slightly diminished," Burnett said. "While it is a significant problem, it pales in comparison to our biggest obstacle, which is lead poisoning... Condors are basically ingesting lead when they forage inland. "
To listen to the full interview, click on the blue audio player above.