In the spring of 2012, our newest wild California condor pair in Baja California, Mexico, identified as #361 and #373, continued to show signs that they were incubating an egg by being more aggressive to the other condors around the feeding site and by spending a lot of time in a remote area dotted by deep canyons and precipitous cliffs. Their GPS wing transmitters indicated a near-exact position of where the nest would be out in the wilderness by latitude and longitude readings. Plugging these coordinates into our handheld GPS, Program Field Manager Juan Vargas and I struck out in September 2012 to try to find the nest, knowing that it was about 15 miles (24 kilometers) out to the remote south of our condor field station.
We traveled light and fast but only made it three quarters of the way there after three days through rough terrain and vegetation. With dwindling food and clean water, we decided to head back. Also, the GPS maps indicated that the nest was very high in precipitous terrain, and we were not carrying sufficient ropes and equipment to deal with it safely. Within condor release programs in the United States, if the nests are too difficult to find or ascend to, scientists rely on waiting for the young to fledge and show up at feeding sites, where they can be trapped and tagged later. We decided to do the same, since verifying the young at the nest would be too costly in terms of helicopter time, which would be the only way we could safely access it.
The downside to this decision was that the chick would not be inoculated for West Nile virus and would run the risk of catching the disease if we could not administer the vaccine. From our field station, Catalina Porras and crew analyzed both radiotelemetry and GPS data and estimated that the chick probably fledged in October. Over the three-months that followed, only the behavior of the parents at the feeding site and their movement patterns continued to give us hope that there was indeed a chick flying around in the backcountry. We continued to scan the skies for a “tagless” condor with a gray head.
Finally, on February 4, 2013, Juan and a crew member observed a juvenile condor showing behavior that stood out from the others. Further scrutiny revealed that the black-headed youngster had no tags. It was hard to keep the excitement contained as we realized that the phantom chick had survived! As the new chick becomes accustomed to the other wild condors and the feeding site over the next few months, we are hoping to trap it, administer the West Nile virus vaccine, and tag it with GPS transmitters so we can safely follow its progress.Three condor pairs are looking like they may produce young this season. With luck, we may find more dark-headed condor young in the skies over the Baja mountains next year as well.