Establish a self-sustaining population of California Condors (Gymnogyps californianus) in the Grand Canyon/Arizona Strip regions of northern Arizona and southern Utah in cooperation with state and federal agencies, tribes, local communities, and the private sector.
California Condors are highly endangered. Only 22 individuals remained alive in 1982. The Peregrine Fund produces condors at the World Center for Birds of Prey in Idaho and releases them in Arizona as a “non-essential experimental population” under a Memoranda of Understanding and applicable special permits with the U.S. Fish and Wildlife Service, National Park Service, Arizona Game and Fish Department, and others.
Non-invasive research into captive breeding and restoration increases the body of knowledge regarding condor conservation and natural science, and provides the basis for ongoing management decisions. Specific topics of field study include condor movements, behavior, foraging ecology, and toxicology, specifically, lead poisoning. Findings and publications arising from these investigations provide guidance to this and other endangered species restoration programs through scientific exchange and publication.
Since 1996, The Peregrine Fund has released 149 condors, documented 22 wild-hatched young, 92 fatalities (54 diagnosed, 38 missing or unknown), and returned 10 individuals to captivity. Captive breeding, release, radio-tracking, and adaptive management has brought the total world population to more than 400.
A fair proportion of the wild population in Arizona and Utah has reached breeding age and has produced 22 young in the wilds of the Grand Canyon, Vermilion Cliffs National Monument, Kaibab National Forest and Glenn Canyon Recreation Area, all in northern Arizona.
The condor flock forages largely on its own. We have identified the principle mortality agent (lead poisoning), its source, and advancements in reducing its prevalence and impact. In this regard, the management agencies responsible for the harvest of game in Arizona and Utah have initiated mitigating efforts to reduce the amount of lead available to scavengers. With continued effort and progress towards reducing lead in the landscape, we are confident that the condor population has the potential to eventually thrive, reaching the recovery goal of 150 individuals. Continued efforts to encourage the use of non-lead alternatives for dispatching animals, wild or domestic, is key to this recovery effort.
The Peregrine Fund has a captive flock of more than 50 condors at its breeding facility at the World Center for Birds of Prey in Idaho. There are 18 breeding pairs, which produce about 20 eggs. Most are hatched in Idaho; others are transferred to other breeding facilities to be placed in wild nests and enhance genetic diversity. All chicks hatched at our facility are parent-reared or foster-reared. Each year, about a dozen juvenile condors are transferred to the Vermilion Cliffs Release Site in Arizona.
We provided contaminant-free food at the release site every three to four days for two main purposes: 1) newly released, parentless condors will need food as they incorporate into the flock for the short-term, and 2) a steady supply of available carrion, in addition to the general trend of condors returning to their “artificial” natal area during breeding season, proves one of our most effective management tools. Because the breeding season begins in winter as natural food sources become scarcer, condors are more readily trapped for needed lead testing, general health checks, and replacement of failing telemetry equipment.
Although condors have gone missing in years past, we always hope they will one day revisit the release area, just as Condor 176 reappeared after being out of contact for nearly five months. However, we have added seven condors to the “missing and/or unknown” category, which now totals 32 individuals. The ever-increasing independence of the flock combined with extensive utilization of habitats in southern Utah and large amounts of inaccessible private property makes it increasingly difficult to track and monitor individuals.
Of 12 pairs of condors last season, six produced eggs, with four chicks confirmed, the greatest number of chicks hatched in any one year for the history of the program. Four of the pairs that did not produce young, two that would have been tending young from the previous year, and two thought to have a good chance of producing were thwarted by death. Two were confirmed as lead-caused deaths and two suspicious of lead relative to the timing and location of deaths. In addition, preliminary investigations suggest that lead exposure negatively influences flock productivity due to necessary capture and sometimes chelation therapy, which interrupts pairing activity by simply being pulled into captivity for treatment during the breeding season.
Our research continues to include observations of lead pellets and fragments in the digestive tracts of lead-poisoned condors, consistent with previously discovered bullet fragments in rifle-killed deer and coyotes fed on by condors. Radiographs of the remains of deer killed with standard lead-based rifle bullets have revealed numerous metal fragments as the normal condition.
The Peregrine Fund continues to focus on lead exposure detection and treatment as the essential element in maintaining the population. Since the summer of 2000, we have continued to trap, obtain blood for lead-level analysis, and treat sickened condors when necessary.
We again found an abrupt increase of blood lead-levels corresponding with increased use of deer hunting areas on the Kaibab Plateau and the Kolob range in southern Utah during the weeks prior to testing. The period of highest exposure is October and November when the deer hunting seasons are underway, and the period of greatest lead-caused mortality among condors is December and January, reflecting the latency of effect.
We collected blood samples (including re-samples) from 96% of the wild population, which yielded slightly higher levels than previous years and 28 individuals were treated for lead poisoning with chelation therapy. The treatment threshold for chelation continues to vary from year to year in an effort to reduce mortality of birds that have been continually exposed for multiple years. Each individual case of lead exposure is independently diagnosed and is based not only on blood-lead level, but on body condition, frequency of previous known exposures, nesting activity, and other variables.
Monitoring of Population
We tracked the daily movements and activities of condors, a task made more difficult by the increasing numbers of free-ranging birds and their widening tendencies toward long-range movement in this rugged region of sometimes limited access. We continue, therefore, to benefit from satellite-reporting PTT/GPS transmitters (Microwave Technology) on some condors. These transmitters record hourly position fixes to within roughly 50 meters of the actual locations, and transfer accumulated data each day to orbital satellite arrays. Although aging units have resulted in fewer complete data sets, careful placement of available transmitters proved especially useful in helping to determine nesting and foraging locations on select birds.
As a result of fewer GPS units, roost relocation data continue to fill in the gaps of known locations of individuals by ground-truthing previously observed and recorded patterns of habitat use. Bird locations are recorded based on presence or absence through visual and/or VHF telemetry-aided ground tracking.
We continued to document what has become the normal trend of extended use of Utah, the northern end of the condor’s general range. From the hills just outside of Zion National Park, most of the birds eventually returned to the release site as the winter snows made carrion more scarce. This period is characterized by an increasing use of the Kaibab and Paria plateaus where condors have continued to encounter lead bullet fragments in the remains of shot mammals. GPS transmitters are especially valuable in revealing the exact locations of condor activity both in real time and in retrospect.
Close monitoring of movements has also aided us in quickly averting behavioral problems that still occasionally develop among inexperienced condors. We conditioned them by hazing, installing aversive conditioning devices in highly used areas when necessary, and confinement for extreme cases. These measures are intended to break patterns of undesirable behavior in relation to humans and artificial structures. Our records show that such conditioning results in improved behavior as the birds mature. We conducted public education and outreach efforts in areas where condors and humans overlap.
|Project History||Notes From The Field|
|Publications and Data||Other Information|
|Photos and Videos|
|California Condor current population data table||Detailed information on released condors|
|Condor Cliffs page on Facebook||AZGFD: California Condor Recovery|
Southwestern United States, with a focus on the Grand Canyon area of Arizona