On Friday, September 18, 2009, we attempted to release three more California condors to the wild at our condor reintroduction site in Baja California, Mexico. We had conditioned the three new birds, numbers 430, 436, and 446, in the large aviary with our adult mentor, Xewe, since they arrived at the site from the Wild Animal Park on March 19. The threesome was transferred a few weeks ago to the release pen situated atop a 2,000-foot ridge, where they could become accustomed to the sights and sounds of the area and see previously released condors use the food and water available to them once they were free. New tags and transmitters were attached on the night of September 13 by the field crew and they were ready to go. However…
This simple scenario is overshadowed by the reality that older condors in the free-flying group have worked out their social status differences, for the most part, and any newcomers must go through an initiation that can be rough, or at least intimidating. So, after opening the 6-foot pen door at 3:30 a.m. on September 17, one of the mid-level, older birds, #362, entered the pen when there was enough light and began harassing #430, driving him out of the pen.
With sort of a forced release, he flew to a hillside a hundred or so yards to the south and began to climb. From a higher vantage point, he was soon able to fly back to the vicinity of the release pen but not without drawing the attention of other older birds that took turns approaching and investigating him up close.
After all the attention (at times there were seven condors playing on the release aviary roof netting), one of the release birds, #446, remained in the pen overnight, one slept in the tall pines toward the cliff, and one, #436, roosted overnight on top of the pen. Over the next few days all seemed to settle in a more normal release routine, with the newcomers taking short exploratory flights and tentatively feeding in and around the established birds at carrion we strategically placed out under the cover of darkness.
Now we hope for a smooth transition over time as they practice flying, learn where to find food, water, roosts, and seek acceptance within the group.
Mike Wallace is a conservation program manager for the San Diego Zoo.
California Condor Recovery Program