| Report questions practices
of condor release program
23 August 00 | Current releases of captive California condors into the wild probably will fail unless changes in the program are made soon, according to a new study published by Berkeley and Indiana University professors.
Researchers, in a report published in the August issue of Conservation Biology, maintain that captive rearing techniques are producing excessively tame condors that pose threats to humans. And the released birds, they said, are at constant risk of death by lead poisoning from eating carcasses contaminated with bullet fragments.
"The California condor program is the flagship of endangered species conservation programs," said the report's co-author Steven Beissinger, associate professor in Berkeley's Department of Environmental Science, Policy & Management. "Large amounts of money have been spent and many individuals have worked hard to breed condors in captivity and to develop techniques for reintroducing them to the wild. Success is definitely achievable, but only if basic changes are made in the current condor release program. If not, it may become a perpetual and very expensive black hole."
California condors once could be found along the Pacific coast from Canada to Mexico. By the late 1970s, only about 30 birds remained. A captive flock was started in 1982, and free-flying birds were captured when it became clear that the wild population was beyond rescue. The last wild condor was captured in 1987. Breeding in captivity was successful, and releases of captive-born young condors to the wild began in 1992. But the death rate of released birds has been too great to sustain a wild population.
"Many condors are reared in captivity by humans using condor-shaped puppets, and this has created birds that readily approach people, cars and buildings," said Vicky Meretsky, assistant professor in the School of Public and Environmental Affairs at Indiana University and lead author of the journal article. In the past year, there have been repeated instances of condors prying shingles off buildings, destroying camping equipment and approaching people for food handouts, she said.
"Behavioral problems have been common in released young condors that were taken from their parents and reared by puppets in isolation, but not in young condors that were raised by their parents," said Meretsky. "Unfortunately, despite this important difference, program managers have continued to release puppet-reared birds to the wild instead of limiting releases to parent-reared birds."
Lead poisoning was a main cause of extinction of the wild condor population in the mid-1980s, and it is killing condors again because releases have been conducted without attempting to solve the problem. In the last few months, five released birds have died of lead poisoning and others are contaminated, Meretsky said.
"Until sources of lead contamination are effectively countered, releases of captive condors cannot be expected to result in viable wild populations," she said.
"To re-establish any wild species, the main causes of its extinction must be identified and eliminated before releases of captive animals are attempted. This basic tenet is being neglected in the current condor release program, even though alternative ammunitions are now available," said Noel Snyder, co-author of the report and senior author of the recent book, "The California Condor: A Saga of Natural History and Conservation."
Part of the problem with the release of condors is that birds raised using puppet condors have been excessively tame, despite efforts to train these birds to avoid humans and human structures. One group of eight birds wound up in a resident's bedroom after tearing through a screen door to enter the house. In Grand Canyon, a condor ripped through the side of a camper's tent as he lay sleeping within.
Only one release site, near Big Sur, Calif., has had a purely parent-reared group of condors, and it has been essentially free of tameness problems, Meretsky said. Unfortunately, these birds recently expanded their range and joined one of the groups containing puppet-reared birds, and now they are beginning to follow the puppet-reared birds into developed areas.
The study strongly urges that future releases be limited to parent-reared birds, especially ones that are raised free of all contact with humans in field enclosures that do not resemble human structures.
Short-term measures to reduce lead poisoning were suggested as far back as the 1980s, when condor releases were first discussed. The proposal was to use only one or two feeding locations to provide condors with uncontaminated food until lead in their environment was no longer a problem. But release programs have instead emphasized more natural foraging patterns, using supplied food to tempt the birds to fly more widely, and then reducing and even eliminating the provision of safe food. First encouraged to feed on their own and then forced to do so, condors are now dying of lead poisoning.
"If lead contamination
persists in the environment and increased feeding on natural carcasses
continues, the mortality rate of released condors will equal the disastrously
high mortality that once drove condors to the brink of extinction," Beissinger
[HOME] [SEARCH] [ARCHIVE] [ABOUT] [CONTACT] [MORE NEWS]
Copyright 2000, The Regents of the University of California.
Produced and maintained by the Office of Public Affairs at UC Berkeley.
Comments? E-mail email@example.com.