The chick stage brought many more hours of observation and entries. In all 18 entries were performed on the six nests during the chick stage. All four nests were found to have trash items of varying degrees during this period (19-233 items). Metal detection and palpation identified metal and foreign bodies many times during chick exams but this did not always translate to stunted development or poor body condition, which were the indicators we used for intervention. There was one occasion of removing trash from the crop of a chick – 60-day-old No. 428 — while at the nest.
Chick No. 450 was temporarily removed from her nest for surgery related to trash. A physical exam of chick 450 at 91 days of age showed poor tail feather growth and labored and rapid respirations. We also observed a decline in activity levels prior to this entry. At 94 days old she was removed from her nest and transported to the Los Angeles Zoo by helicopter where Dr. Wynne performed surgery on the chick, removing an impaction of trash items and hair form her ventriculous. She was also diagnosed with bacterial pneumonia and treated with antibiotics before being returned to the nest 23 hours after her removal. An additional entry followed up this treatment a week later so that antibiotics could again be administered and the surgery’s suture could be checked. Observers tracked her recovery as activity levels increased and following exams showed resumed feather growth. All other entries were conducted without event with the help of the L.A. Zoo condor keepers and veterinary staff, who deserve our thanks for enduring the long and steep bushwhacks and climbs in the brutal heat of the summer months.
All chicks in Southern California had their wings fitted with VHF transmitters and tags at about 100 days of age. The decision to place patagial-mounted transmitters on chicks was not without concern as there have been some physical problems recently with wing-mounted transmitters on free flying birds. In the event of a transmitter malfunctioning or riding improperly, it would be sometime before chicks could be trapped at feeding sites for replacement or repairs increasing the chances of wing damage. These concerns were weighed against the increased ability to gather data on naturally fledging chicks, something that has not been accomplished in the past, and in the event of a problem provide the ability to intervene on the newly fledged chick’s behalf. Thus far, the transmitters have been extremely valuable in both tracking the active chicks progress as they move away from the nests to more remote locations and during the Ranch Fire. The location of condor 443 post mortem was also determined via radio telemetry. The transmitter of No. 450 has been observed in a flipped position and there is concern to the way that it is riding. This may have been due to the small cavity size of this chick’s nest where the chick may have caught its transmitter on the cavity walls while wing flapping. All other transmitters are riding without observable reason for concern. In 2008, we will be looking closely at new transmitter attachments for chicks.
Fledging came at a variety of ages for these chicks. The youngest being No. 443 took flight from the nest cliff after being harassed by an adult female from the population at 142 days old. Despite the continual harassment by this adult female, chick. 443 continued taking short flights down low in the canyon and quickly learned of other threats from terrestrial predators (black bear and bobcat) that were observed in the vicinity of her location in the lower canyon region. Regrettably, at 23 days later this chick was discovered deceased at a location about 500 meters from where she was last observed. The direct cause of her death has not yet been determined but it is likely to due to post complications following the Ranch fire, which burned through the area and the Hopper Mountain National Wildlife Refuge in late October.
The oldest chick, No. 428, fledged at 155 days of age when she was observed taking short flights to a more removed portion of the nest cliff. Her progress has been tracked closely over the last few months and has been observed several times flying over and feeding at Hopper Mountain with her parents (about six miles from her nest site). We have been relying primarily on radio telemetry and the occasional visual to track her progress as she continues to integrate with the rest of the free flying population.
Condor 450 fledged at 179 days old on Nov. 10 – a true sign of her recovery from surgery She still remains within the nest canyon but has began roosting with her parents in a snag about 50 meters from the nest cavity. Her location makes this chick the easiest of the fledglings to observe allowing us to closely follow her interactions with her parents.
The final chick to fledge did so at 208 days of age. Chick 449 has been taking short flights and spending time on the cliff faces immediately across the canyon from the nest site. This chick seems to have of a delayed age of fledging relative to the rest of this season’s chicks. A possible explanation for this could be related to the topography in the immediate vicinity of her nest site, which is much less vertical and allows her to venture out distances of about 60 meters without taking flight. Two of the newly fledged chicks, 428 and 450, have also been observed interacting with golden eagles. In these cases the eagle has aggressively swooped down on the chicks often making contact and grounding the chicks around their nest cliffs. We have not observed any injury as a result of this aggression but this certainly could be a threat. If the parents are in the vicinity they defend the chicks by chasing the eagles away.