A review of the 2007-2011 period of the California condor reintroduction program in northern Arizona and southern Utah was recently completed and identifies a number of successes, including an increase in the free-ranging population, consistent use of seasonal ranges by condors and an increased number of breeding pairs. However, exposure to lead contamination from animal carcasses and gut piles left in the field continues to limit the success of the program. The team made several recommendations to address the lead issue.
At the end of 2011, there were 73 free-ranging condors in the Southwest population – an increase of 16 birds during the review period (there are presently 76). A total of 41 captive-raised birds were released into the population. Ten chicks were wild-hatched during the 5-year period, and 7 of them died or went missing. An additional 24 adults died or went missing, and five birds were returned to captivity.
During this review period, the condor population began spending a greater portion of the year in southern Utah rather than staying in the vicinity of the Vermilion Cliffs release site or the Colorado River corridor.
As the wild population has matured, there has also been increased breeding activity with five to six pairs attempting to breed each year during this period and one to three chicks produced each year in Arizona.
Lead poisoning remains the primary diagnosed cause of mortality in the population. Lead poisoning cases occur predominantly in the fall and winter months and are associated with the big game hunting seasons, although incidents have occurred during the spring and summer and can often be attributed to varmints and dispatched domestic animals left in the field. Program biologists attempt to trap every bird in the free-flying population before and after hunting season. Between 85 to 97 percent of the population was tested for lead exposure during each year of the reporting period with 27 to 56 percent of those tested treated (chelated) for lead poisoning.
Since 2005, the Arizona Game and Fish Department has conducted a voluntary lead reduction program with 83 to 90 percent of successful Kaibab-area hunters voluntarily participating in the past five years. The Utah Division of Wildlife Resources initiated a voluntary non-lead ammunition program for the Zion Wildlife Management Unit in southern Utah in 2010, but plans to expand the effort this year to increase participation.
In the spirit and intent of the Endangered Species Act 10(j) non-essential, experimental population rule establishing the Southwest condor population, the review team believes that addressing lead-caused mortality would enhance the success of the program, but such efforts should be voluntary.
The team did not recommend removing and relocating the condors in the Southwest population to California or Mexico as those areas do not afford any greater realized protection than the release area in the Southwest. Ultimately, the reintroduction partners will seriously consider withdrawing support for condor reintroduction efforts in the Southwest if, by the end of 2016, a reduction of extreme lead exposures (blood lead levels) is not achieved and a declining trend in diagnosed lead related mortality and morbidity is not observed.
The review was conducted by the program partners (the team) including the U.S. Fish and Wildlife Service, Arizona Game and Fish Department, Utah Division of Wildlife Resources, The Peregrine Fund, Grand Canyon National Park, Bureau of Land Management and many others.
The experimental Southwest condor reintroduction project began with the release of six condors at the Vermilion Cliffs in Arizona in 1996. This is the third 5-year review of the program.
The goal of the California Condor Recovery Plan is to establish two geographically separate, self-sustaining populations: a primary population in California and the other outside of California, each with 150 birds and at least 15 breeding pairs.
Image courtesy Arizona game and fish department