Thick billed parrotA SEVEN-YEAR effort to return thick-billed parrots to the pine forests of Arizona where they once thrived has failed because birds raised in captivity floundered in the wild, quickly becoming prey for hawks.
Some of the birds starved, others succumbed to disease, but most were eaten by predators, often within 48 hours of their release. Researchers have suspended the project, saying they are uncertain whether any of the 88 parrots released in the Chiricahua Mountains of southeastern Arizona from 1986 to 1993 survived.
Reintroducing a dying species to the wild, even in its native habitat, is never easy, conservationists say. In fact, most attempts fail, especially when they involve animals born in captivity. Yet wildlife researchers say that such efforts tend to be more popular than other conservation techniques, like those that rely on legislation and public education.
To be sure, the appeal of returning the brightly plumaged thick-billed parrot to Arizona is largely esthetic, said Dr. Noel Snyder, an ornithologist who directed the parrot project and led the attempt to revive the California condor in the late 1980's. The thick-billed parrot, which is rather tame and not a prolific talker, is one of only two parrot species native to the United States. The other, the Carolina parakeet, went extinct early in this century.
The thick-billed parrot is an emerald green with scarlet shoulder patches and a red nose. It disappeared from the southwestern United States in the early 1900's, a victim of hunters, but large flocks of the parrot still nest in the western Sierra Madre of Mexico.
The attempt to resurrect the species in Arizona began with 29 wild adult parrots that the United States Fish and Wildlife Service had confiscated from smugglers. Later, another 36 wild parrots were added. But the flocks dwindled considerably after a drought in 1989. Illnesses, such as an incurable, fatal wasting disease, took a toll as well.
The project encountered its most formidable challenge when it supplemented the wild parrot population with birds that had been raised in captivity. In their native habitat, thick-billed parrots are loud and gregarious creatures. Among the speediest parrot species, they streak through the sky, wingtip to wingtip, holding a tight, V-shaped formation. A robust thick-billed parrot can easily outfly goshawks and red-tailed hawks, its main predators, and sometimes even a peregrine falcon.
On the ground, the parrots seek safety in numbers, nesting close together in Ponderosa pine trees or Douglas firs at altitudes of 7,000 feet or more. Often, one bird will act as a sentinel for the others, perched on a treetop and calling vociferously when danger approaches.
The 23 parrots raised in cages lacked those flocking instincts and, more importantly, proved unable to develop such survival skills in the wild. Liberated, they took solo journeys to other mountain regions, foraged for pine cones in forests that had no pine trees and showed a lack of interest in socializing with their fellow avians.
"They get out there and the whole thing seems to be such an overwhelmingly new situation that they sit there dazed," said Dr. Snyder. "They don't flock properly, so they are very vulnerable to predation."
To improve the birds' chances, the biologists created what amounted to training sessions in how to behave like a thick-billed parrot. Housed in 30-foot-long cages with wild parrots, the ones raised in captivity learned through a combination of imitation and trial and error how to feed themselves.
"That's a tricky thing," Dr. Snyder said. They must snip a pine cone off a branch and then maintain a firm grip while using their thick bills to extract the seed.
The training helped hone the parrots' foraging skills, but it did not improve their flocking strategy. In one typical release, a female thick-billed parrot quickly located a wild flock and took up a perch about 33 yards away. When the flock returned to its feeding area, the female flew to another canyon. She was killed by a raptor later that afternoon.
"We reached a point where we were putting out the best candidates of captive-bred birds and just watching them die," said Susan E. Koenig, a volunteer in the program who wrote her master's thesis on thick-billed parrot behavior for the University of Arizona in Tucson. "Ethically, we couldn't justify putting out more captive-bred birds just to feed the hawks."
Wildlife Preservation Trust International invested $276,000 in the reintroduction program, some of which was a contribution from the Arizona Game and Fish Department. From the beginning, the project faced dismal odds. Only about 1 of 10 reintroduction schemes that use animals raised in captivity leads to self-sufficient populations of 500 or more individuals, said Dr. Benjamin B. Beck, associate director for biological programs at the National Zoological Park in Washington, who has reviewed 145 such projects.
The most successful reintroduction programs involved large numbers of animals over several years, Dr. Beck said. They also relied on public education programs to foster local support and enthusiasm.
"They capture the imagination," said Dr. Mary C. Pearl, executive director of Wildlife Preservation Trust International, a nonprofit organization based in Philadelphia. But she said most reintroductions occur when the species is in its last gasp. "That's almost certainly a prescription for failure," she said.
While the thick-billed parrot is not in such dire straits, conservationists say that a renewed North American population could become a critical safety net for the endangered Mexican birds, whose habitat is under siege by loggers.
In the next several years, Dr. Snyder, working with conservation groups in Mexico, will study that population. If they discover a healthy and sizable group of parrots, they might again try to rekindle a group in Arizona, but strictly with birds caught in the wild.