Lessons learned may keep condors on upward wing
California condors benefit from a 'mentor' bird in programs to reintroduce them into the wild.
BAJA CALIFORNIA, MEXICO
Viewed from the perspective of a soaring California condor, the Sierra San Pedro Martir is the great spine of Mexico's Baja Peninsula.
Below, the mountains unfold, revealing miles of ancient Jeffrey pines, bright aspens, cold and tumbling creeks. The deserts yawn on either side, stretching away to the multihued salt pans of the Sea of Cortes on the east, and to the fog-shrouded Pacific Ocean on the west.
It is here, in this silent, remote place, that researchers hope the California condor - one of the largest birds on earth, with an adult wingspan of nine feet or more - will gain a foothold and climb back from the edge of extinction.
In October, the first three condors were released from an acclimation pen perched high on the rugged western ramparts of these mountains, within the confines of a national park. Two more will be released over the winter.
This isn't the first time condor re- introduction has been tried. Researchers have been conducting a controversial captive-breeding program since 1987, when the last wild California condors were captured in a desperate attempt to rescue the species from decline. Seventy-six condors are now living in the wild in California and Arizona. But mortality rates remain high, and wild-breeding success is still too slow to bring the species out of danger.
With this new release in Baja, researchers hope to finally make use of the many lessons they've learned from past mistakes - testing out a new rearing technique and releasing the birds in a region that has fewer threats. They are trying to establish the birds at the southernmost point of their historic range. One day, they hope, the condors will fly northward and unite with populations that have been established in the Sespe Condor Reserve in Ventura County, Calif., or with condors occupying the Ventana Wilderness near Big Sur.
"We have records of California condors from the Sierra San Pedro Martir that date back to the 1930s," says Mike Wallace, leader of the California Condor Recovery Team and a longtime researcher with the San Diego Zoo. "Everything they need is still here, but at least some of the dangers that our US birds face are much less prevalent."
High voltage power lines, for instance, which pose the greatest threat to the birds in the US, do not exist in this part of Baja. Lead poisoning, from bullets or pellets the birds consume with carcasses of game animals, is less likely, in part because there is little game and few hunters here. And the armed recreationists who throng US public lands and cannot seem to resist shooting at big flying targets are largely absent.
Condors have vast home ranges and seem to acquire an encyclopedic knowledge of their territories through slow wandering flights that occupy most of every day. In stark contrast to a world dominated by the race of human activity and technology, the birds live and breed at a glacial pace. "They raise only one egg every two years," says Bruce Palmer of the US Fish and Wildlife Service. "It takes that long to raise a fledgling. Nobody really knows how long they live, but the guess is from 40 to 50 years."
During the years when US farmers used the pesticide DDT, condors suffered the same reproductive losses as raptors such as hawks and eagles. But since condors depend on carrion rather than live prey, they also fell victim to the poisoned carcasses and baits used in the campaign to exterminate livestock predators. The combined threats almost destroyed the species, says Mr. Palmer.
Condors possess extraordinary intelligence that sometimes works against them, Mr. Wallace says. "The best way to understand them is to think of [them as] a social scavenger a lot like a social predator - like a wolf, or a primate." They interact with a group and can't operated solely on instinct, he adds. Their intelligence - like humans' - must be learned."
This posed a problem for captive breeders who, by necessity, had to raise some nestlings by hand. Because researchers were trying to maximize numbers of condors, they removed eggs from nests and placed them in incubators to hatch, so that breeding pairs would produce a replacement egg that same season. The technique is known as "double-clutching."
Because the birds are so social, they raised the nestlings as a group, and released them together, without any older condors, Wallace says. "The group proved to have fantastic curiosity, but almost no caution whatsoever, almost like a youth gang. On days when the winds were right, they would all fly over to the Pine Mountain Club and watch the outdoor barbeque. Other days they would circle a parked pickup truck and then swoop down and tear off the windshield wipers. It was like Lord of the Flies."
Such adventures (which later included mass vandalism of buildings and equipment at the Pine Mountain Club) came with a price - a 15 percent mortality rate in the released birds and some loud opposition to condor recovery efforts in southern California.
The Baja release will be the test of a new rearing technique, where the nestlings have been fed by a condor-shaped "glove puppet" that Wallace developed. They were also kept in close proximity to a group of older condors so that they could be observed and learn from their behavior. "In the wild, condors are raised alone, in a secluded nest, with two parents who are really very stern, hierarchical," Wallace says. "There's no big rumpus, and it produces a more timid, cautious bird - one more likely to survive."
To reinforce that caution, the five condors released in Baja are accompanied by an adult female "mentor bird" that will remain in the acclimation pen for as long as necessary, before returning to the Los Angeles Zoo.
On the day of the October release, a ceremony was held on a ridge across a deep canyon from the acclimation pens. "Sixty years have passed without condors in Mexico, and today we will see these birds open their wings where their ancestors once did," announced Exequiel Ezcurra, president of Mexico's National Institute of Ecology, to the crowd assembled among the enormous pines.
Among those listening as Dr. Ezcurra hailed the release as a new chapter in binational conservation efforts was Andrew Meling, a rancher in his 70s - the last person to record seeing the condor in these mountains.