With condor No. 220 now at six years (the youngest breeding females in the program laid eggs at 5 years old but the norm has been older by several years) and No. 261 at 5 years old we were watching Baja California birds for sexual displays between the expectant “pair” in the spring of 2006 when their soap opera took yet another turn. Most large mammal predators take advantage of fresh carrion given the right opportunity and conditions. Bobcats, coyotes and pumas regularly visited the carcasses of cows, horses and goats that we place out for the condors. Our still “capture cameras” indicated that most of this activity occurred at night but sometimes mammal predators fed in the day as well.

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.

You can follow any responses to this entry through the RSS 2.0 feed. Scroll to the end to leave a comment. Pinging is not allowed.