One of the California Condors recently released in northern Arizona was found dead at the base of the Vermilion Cliffs Friday (10 January 1997) afternoon. A seven-month old male hatched and reared by its parents at the Los Angeles Zoo, was the apparent victim of an encounter with a Golden Eagle.
The bird's carcass was located early Friday afternoon by the field crew leader, Mark Vekasy of The Peregrine Fund. Initial field observations indicated the bird's death was the result of an attack by a Golden Eagle. Results of a preliminary postmortem examination conducted by Dr. Bruce Rideout, Director of Pathology, Zoological Society of San Diego, concur with this cause of death.
Since its release into the wild with five other California Condors on the Vermilion Cliffs, 30 miles north of Grand Canyon National Park, the bird referred to as number 42, never demonstrated the social skills typical to wild condors. It roosted alone and took a six-day, lone sortie to the North Kiabab Plateau, miles from the rest of the flock before having to be captured by field crews and returned to the Vermilion Cliffs. Predators, such as eagles, are able to key in on such abnormal behaviors and this may have made number 42 a likely target. The remaining five condors appear to be healthy and have developed a tight social unit possibly making them less vulnerable to predation. Regular updates on the condors released on the Vermilion Cliffs are being placed on The Peregrine Fund's web site (http://www.peregrinefund.org).
Extraction of Postmortem Findings
"The bird was in excellent physical condition. There was a perforating skull wound approximately 5 mm in diameter, which entered the left cheek, extended through the left orbit (without rupturing the globe), and passed into the cranial vault adjacent to the optic chiasm (the optic chiasm is the point at which the right and left optic nerves join before entering the brain). There was trauma to the base of the brain in the region where the puncture occurred. The lack of any exit wound, and lack of any metallic densities on the postmortem x-ray films, would rule-out a bullet wound. Based on the history from the field biologist and the trajectory of the perforation, one likely possibility is that this perforation was caused by a talon of a Golden Eagle. The lack of other significant trauma or feather damage raises the possibility that this bird was struck while on the ground, rather than in flight, but additional information will be needed to establish the plausibility of this. Although a talon strike from a Golden Eagle is the most likely scenario based on presently available information, this is still speculative and based only on preliminary postmortem findings. Histopathology is pending and a final report will follow. Based on the degree of autolysis, this bird was probably dead for 24-36 hours, 48 hours maximum. Histopathology will be helpful in verifying this." Dr. Bruce Rideout, Director of Pathology, Zoological Society of San Diego.
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