Before we learned to provide “cat food” at some distance in cover the felids preferred, one desperate puma camped out for several days near a condor feeding site and would lunge aggressively at any intruders near the burro it claimed including our free flying condors. It was during this period that No. 220, who was attempting to feed on the carcass with the others suddenly appeared missing her entire tail except for one feather. Possibly a slow learner, she apparently had forgotten about an incident three years earlier when she had lost three tail feathers to an attacking puma under similar conditions.

The field crew reported that she seemed to have no problems flying and keeping up with the other birds during local and distant flights but the increase in aggressive interactions between her and the immediately subordinate females indicate otherwise. Direct behavioral observations became more sporadic as our released population of 11 birds began spending more time in the remote precipitous canyons of the east side of the sierras. It was unclear to us as the beginning (December) of breeding season approached which female of the three contenders we might see interacting with our only possible breeding male, condor 261, since No. 259 had died of lead poisoning a year earlier.

Since the GPS/satellite transmitters cannot find signals to either download or upload information to satellites when condors are in a nesting cave our best technology was nearly useless. In the deep granite canyons their radio transmitter signals were reduced and distorted as well making documenting any nesting attempt challenging.

By noting the whereabouts of all the potential breeders, we looked for who was “not” present when the rest of the population was accounted for in the GPS position data set. Since we know that incubating pairs switch off the egg every four to seven days and the only available male at the time was No. 261, we focused on which of the three adult females was missing and potentially on an egg when we could get his activity readings. When the pattern finally emerged it was not condor 218 nor No. 220 but condor 217 who he had finally chosen as a mate. By relying on their radio transmitters we eventually found the nest verifying that the once shy, subordinate female No. 217 had laid a fertile egg and later hatched a chick. Unfortunately the chick died before 30 days old but the loss might have been related to the pair’s inexperience. They had laid the egg in an old golden eagle nest and the ectoparasite build up may have been what killed it or a territorial golden eagle may have predated it; we were unable to find the chick at the 30-day nest check.

As we watched mate selection unfold in this young population of condors it appeared that health and fitness play important roles not only in who attains high social status but also, in maintaining it over time. Even seemingly small changes in health can make a significant difference in ones social status affecting their relations with all individuals in the flock.

The process of achieving the primary goal for all individuals, to efficiently leave as many “successful” offspring in the next generation as possible, becomes more interesting with species that incorporate social mechanisms to enhance their competitive edge. While condors may look different from mammalian social species that we are more familiar with the social mechanisms seem universally the same.

Whilst contemplating the remaining skin and bones, I also pondered the dilemma of how to provide regular meals to the condors without all the meat going to the other carnivores in the region. Later that day I consulted with Juan Vargas, one of the Mexican field managers for the condor reintroduction site in Baja. Juan decided to place the following morning’s carcass at a different location so that the widely ranging and sharp-eyed condors would hopefully find it before any other animal. Unfortunately, the next day we peered through our binoculars at said carcass being devoured by another two coyotes (who seemed to be quite pleased with themselves). Frustrated, we spent the remainder of the day locating a suitable rocky outcrop upon which to design and build a new, more secure condor “restaurant”.

We found a good-sized (16 ft. long by 26 ft. deep by 15 ft. high), flat-topped granite projection close to the condor release pen on the western cliffs of Punta San Pedro. The outcrop has steep sloping sides to prevent any four-legged creature from climbing up and getting into the carcass before the condors. To be doubly sure, we strung an electric fence around the sides to give a rude shock to anything that tried.

Since this new condor-feeding site with improved security has been built, not a single carcass placed on it has disappeared down the gullet of anything but a California condor! Such is the nature of the condor reintroduction program. It demands that managers and researchers continuously find creative solutions to new and unforeseeable challenges and issues.

Two members of the Chapultepec Zoo’s staff caught a California condor in preparation for its yearly veterinary check up.

Michael Mace, San Diego Zoo’s Wild Animal Park curator of birds restrained a California condor while Dr. Fernando Gual-Sill, general director of Zoological Parks and Wildlife in Mexico City, listened to the bird’s vital at the Chapultepec Zoo in January 2008.

In the end, the birds were healthy and the partners joined together with members of the U.S. Embassy in Mexico in front of the condor exhibit to discuss future plans for the Chapultepec Zoo’s involvement in the recovery of North America’s largest bird.

Along with the staff at the Mexico City zoo, we preformed annual health exams on two California condors that we sent from the San Diego Zoo’s Wild Animal Park to Chapultepec Zoo in 2007. This endeavor was mutually beneficial by exchanging medical information and share condor management and husbandry protocols.

On the evening of the Jan. 16 we met with representatives from INE, PROFEPA, US Embassy, USFWS and Chapultepec Zoo staff to discuss the next phase of the Zoo’s involvement in the California Condor Recovery Program that would include the development of a breeding facility at Chapultepec Zoo. Offspring produced through this facility would be considered release candidates to support the San Diego Zoo’s Baja California release efforts.

During the development of this international program Aeromexico has been generously participating by providing airline tickets to participants as well as cargo space to safely transfer condors to Mexico City.

This additional program in Mexico City has been another milestone for the California Condor Recovery Program. The arrival of the two condors from the Wild Animal Park last year marks the first time in history that the California condor has been in public view outside the US.

Everyone that has been involved in the effort has been so helpful as we continue to collaborate internationally to save this unique species.

Michael Mace is Curator of Birds at the San Diego Zoo’s Wild Animal Park.

It wasn’t long before we realized that #261 not only maintained his flying superiority over all the other condors but, with his beak healed, he was steadily climbing the social status ladder. He could easily out fly and harass the other birds in flight and somehow that flying edge seemed to translate to dominance at the carcass as well. It all seems logical now that a social flying species would spend a good portion of their airtime in dominance interactions. Perhaps condor challenge bouts in the air are equal to or even more important a mechanism for status determination than interactions we can document on the ground around a food or perch resource.

As #261 gained dominance over the 3 older females our observations of their “affiliative” interactions (who likes to be close to whom) indicated that a relationship was building between him and the previously alpha bird in the group, female #218. They could be seen feeding more closely with more tolerance than one would expect, teaming up aggressively on others and “allorubing”; making contact with the bare skin of their necks in an affiliative way. Although breeding age of 5 to six years old was still a few years away, we wondered if we were witnessing insipient pair bonding that would eventually culminate in territorial defense and a nesting attempt.

Just as this hierarchal pattern appeared to stabilize with #261 and #218 as a likely pair at the top, we documented a rapid shift. Four birds, including the “pair” made a several day excursion to the south but only three returned. A day later #218 finally made it back but was obviously limping with a swollen left foot. The ailment eventually healed on its own over a two-month period but not without noticed by her challengers, # 220 and #217. Taking advantage of #218’s compromised physical condition, #220 was able to quickly establish herself as the most dominant female of the group. It was clear that #218 had lost favor with the dominant male #261 as they spent less and less time together. We noticed within two months, however, that #220, now the reigning dominant female was taking long flights together with #261 and soon they could be seen feeding with lowered aggressive interaction and deference between them at the carcass. She now appeared to be the favored one and made that clear to the other more subordinate females. What will happen next as #220 reaches breeding age? Check back with us to find out.