During routine health exams using the field lead care kit on November 18, it was discovered that five out of eight California condors that are part of the California Condor Recovery Program in Baja California, Mexico, had elevated levels of lead in their blood. On November 23, all five condors were returned to the San Diego Zoo's Harter Veterinary Medical Center (HVMC), located at the Wild Animal Park, a USDA-approved quarantine facility. Chelation treatment was initiated.

Twelve additional condors in the Baja release area were tested for lead on November 25; five proved positive and were also relocated to the HVMC on November 26 for chelation treatment. By December 2, all 22 California condors in Baja California had been tested and 11 of those had lead levels high enough to require treatment. Of the first five birds radiographed, one bird retained a shotgun pellet in his gut . A more refined analysis of blood lead levels from an outside lab is pending. Chelation therapy is expected to continue over the next two to three weeks with weekly retesting of blood lead levels. The birds are expected to return to the field as soon as possible after their lead levels are brought to an acceptable range. Fortunately, no birds are showing any symptoms of lead intoxication at this time.

Live and dead large domestic animals are bought from local ranchers to feed the condors, and staff has had to rely on the owners, when possible, for the animal's health history. Since both free flying and pre-release captive birds were affected during this recent episode, it is likely that the lead was in food that was fed to both groups. After the lead poisoning case in Baja of captive condor #319 in 2005, staff has been using a metal detector to scan each carcass (horse, cow, or goat) for lead from potential gunshot wounds acquired earlier. This technique only detects gunshot pellets close to the surface of the skin; apparently there is still sufficient risk that lead shot deeper in the tissue can go undetected.

To reduce the risk of lead contamination in the future, the San Diego Zoo will be acquiring field digital X-ray equipment to ensure that each carcass offered to condors in Baja will be free of lead.

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California Condor Recovery Program
Zoological Society of San Diego's position statement regarding the threat of lead poisoning in the environment