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Biologists at Pinnacles National Monument were alarmed to find California condor 307 had dangerously elevated blood lead levels after finally capturing her last week. Initial field tests returned readings or 46.8 and 47.4 micrograms of lead per deciliter of blood (µg/dL). “Field readings at this level are disturbing because lab results have consistently been 40 to 50% higher” explained Court Van Tassell, Wildlife Biologist for PinnaclesNational Monument. Park biologists immediately began chelation treatments (shots of calcium EDTA, a compound that ‘collects’ lead in the blood and allows the bird to eliminate it from their system) on the evening of July 3, 2006. “Capturing 307 was difficult because she became spooked when we began trapping and she flew over to the San Luis reservoir area for three days before returning to the monument” said Van Tassell. “Her weight is still lower than we would like, about 15 lbs, but she is becoming more active and feeding more. We will be holding her for further observations and feedings for at least another week.” The remaining captured birds have been re-released into the wild.
The Pinnacles condors may still face health problems because of the elevated levels of lead in their blood. While the levels measured are not high enough to warrant emergency measures, long term exposure to non-lethal levels remains a serious problem. Lead in a condor’s bloodstream will be absorbed into its bones, where it can slowly leach back into the blood for more than a year.
Because the potential for re-exposure still exists, Pinnacles is organizing a series of community forums to discuss how everyone can work together to help the California Condor survive in the wild. They will be held from 6:30-8:00 pm at JeffersonSchool (Tues. July 25), King City Library (Wed. July 26), San Benito Co. Library (Thurs. July 27), and the Soledad High School Mission Room (Mon. July 31).
The vast majority of research on the health effects of lead exposure is based on humans, but comparisons can be made for animals. When a child's brain is developing, even low levels of lead in the body can slow the child's development and cause learning and behavior problems. It can change the way blood-forming cells work, alter the way nerve cells signal each other, and disturb or destroy the way the brain makes connections for thinking. Some of the Pinnacles condors tested at three times the level that would initiate a medical response in humans as outlined by the Center for Disease Control. At this time, the effects of lead exposure on juvenile condors are only measured in mortality rates.
The local ranching community has shown increasing support for the Condor Introduction Program. Ranchers helped biologists place a remote trap to capture the condors roosting outside the park after the birds were seen feeding on rodents that had been shot with lead ammunition and ranchers many have committed to using non-lead ammunition. Without their efforts, this opportunity to bring California condor back into the wild will not succeed.
Jim Petterson, Supervisory Wildlife Biologist, PinnaclesNational Monument, 831.389.4485 x 223
Denise Louie, Chief of Research and Resource Management, 831.389.4485 x 222
Chris Ketchum, Ranch Foreman, Paicines Ranch, 831.801.7910 (Local rancher who switched from lead ammunition to copper in response to the condor reintroduction)