After the suspicious death of condor #390, the most subordinate condor of the 16 free flying birds in Baja, we stepped up our routine annual health exams for the 22 condors both captive and free flying in Baja. On Sunday, November 18, 2007, we discovered 5 out of 8 birds tested to have high lead poisoning using the field lead care kit (HIGH being 65 ug/dl, the limit of the equipment). On Friday, November 23, all five condors were transported to the Wild Animal Park’s Harter Veterinary Medical Center, a USDA-approved quarantine facility, and chelation treatment was initiated.

The treatment consists of daily administration of two doses (one injection and one oral) of calcium EDTA that binds to the lead in the blood and flushes it out through the kidneys. Baring complications, high lead levels in blood can be reduced to near background levels within a few weeks, and in most cases, birds can be released back to the wild.

Heavy sleet/rain (over 4 inches) and winds (over 60 kts) made trapping some of the condors in Baja challenging. Field assistants Juan and Catalina did an incredible job during this event. However, field conditions and a recent drop in field staff made it impossible to efficiently and safely treat the birds in Baja.

With trapping ongoing, we tested 12 additional condors for lead on Sunday, November 25. Five more proved positive and were relocated to the Wild Animal Park on November 26 for chelation treatment. Days later, the last two birds were tested. One proved positive and was also transported north. Of the 22 birds in Baja, all were tested; 11 were positive and in need of treatment. All birds were radiographed on arrival at the hospital and only one, #323, retained a single shotgun pellet in his gut. Attempts to retrieve it by flushing the GI tract and using a laparoscope have been, so far, unsuccessful but efforts will continue.

Condors are very hardy birds. To give some perspective, bald eagles that Dr. Pat Redig at the Raptor Center at the University of Minnesota treats for lead toxicity often die at lead contamination values just over 100 ug/dl. During the course of treating these condors, a more refined analysis of blood lead levels from an outside lab indicated that lead values in all birds were well over the 65 ug/dl (as indicated by the field lead test kit) and some values as high as 590, 600 and 640 ug/dl. Unfortunately, condor #325 died suddenly while the group was being treated. We are not sure whether it was related to the lead intoxication, the treatment, or a combination of these and other unknown factors. Of the many dozens of condors treated in this way, only two other condors have died under similar circumstances.

Since both free flying and pre-release captive birds were affected during the recent episode, it is likely that the lead was in food that we fed to both the captive and free flying groups. We buy live and dead large domestic animals from local ranchers and have to rely on the owners, when possible, for their health history and our site manager Juan’s inspection of the carcass. After the lead poisoning case in Baja of captive bird 319 in 2005, we have been scanning with a metal detector each carcass (horse, cow, or goat) for lead from potential gunshot wounds acquired earlier in the animal’s life. This technique works, but unfortunately it is only effective to a few inches in depth, which apparently still leaves sufficient risk that lead shot deeper in the tissue can go undetected.

To reduce the risk of lead contamination in the future, we acquired field, digital x-ray equipment so each carcass proffered to condors in Baja can be entirely scanned for lead prior to being fed to the birds. While cumbersome, this technique should drastically reduce the risk of future lead contamination exposure.

As reported by Wild Animal Park veterinarian Dr. Jeff Zuba, all our condors were off treatment (lead levels less than 30 ug/dl) by January 10, 2008. (Treatment lasted 1.5 to 6 weeks, depending on the contamination level of the bird.) How quickly we can get the affected condors back into the field will determine the overall negative impact to the program. With the exception of a few glitches, all agencies contacted on both sides of the border have been immensely helpful to this point. CITES permits to re-export the birds have been applied for out of Dave Rimlinger’s office at the San Diego Zoo.

Again, I would like to thank all those involved with this operation including the Baja condor field staff, the keeper, vet-tech and vet staff at the Wild Animal Park. Mike Clark for coming from LAZ to assist in training the hospital keeper staff. USDA, PROFEPA and USFWS have been exceedingly corporative and helpful during the transfers with Dr. Fernando Sanchez coordinating the many details on the Mexico side. Dr. Jeff Zuba supervised many transfer details and coordinating the hospital treatment. The keeper staff at the hospital did an amazing job of managing the eleven condors considering safety, behavioral isolation and USDA quarantine. Only after re-release to the wild will we be able to determined the behavioral effect this experience has had on the birds.

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