PHOENIX - Nine California condors hitched a ride on an airplane Monday from Boise, Idaho, to their new home near the Grand Canyon.
The three males and six females are the latest birds sent out in a reintroduction effort that wildlife officials say has been more successful than expected.
California condors, among the most ancient of North America's birds, were shot, poisoned and electrocuted to near extinction until biologists launched a multimillion-dollar recovery program in the 1980s. Condors were first released in Arizona in 1996.
The latest batch of condors will bring number of the giant birds in Arizona skies to 29 - more than the world's total when the program began. Worldwide, there are 168 of the vulture-like scavengers, 49 in the wild in Arizona and California and 119 in captive breeding facilities.
''The condor reintroduction program has been doing fantastic in the state,'' said Rory Aikens, a spokesman for the Arizona Game and Fish Department, one of several state and federal agencies coordinating the effort.
Aikens credits the states ''prime condor habitat'' in the Hurricane and Vermillion cliffs north of the Grand Canyon, as well as support of residents in the area.
The birds, too, are doing their part.
The condors this summer found food on their own rather than relying on provided carcasses, said Jeff Humphrey, spokesman for the U.S. Fish and Wildlife Service in Phoenix.
But the birds' foraging independence - which came sooner than expected - is a mixed blessing, he said.
''It shows they are adapting to the wild but it also makes them more difficult to manage because provided carcasses keep them in a certain area,'' he said.
Program managers are even more excited that a male condor recently tried to court a female by bobbing his head and spreading his wings, which have a nearly 10-foot span, Humphrey said.
''We don't know what it means, but it means something to female condors,'' he said.
Although the birds are approaching the breeding age of five years, program officials say they don't expect a successful mating at least for another year.
''They have bred in captivity in their fifth year but things progress much slower in the wild,'' Humphrey said. ''In the wild, food sources are less reliable ... so they have less opportunity to pay attention to sex.''
In the wild, condors typically lay one egg every other year, but they can lay up to three eggs per year in captivity.
The discrepancy is partly because in captivity, managers take the first egg and incubate it mechanically, causing the condor to lay another egg said Bill Heinrich, species restoration manager for the Peregrine Foundation. The second egg is hatched and raised by the mother, he said. The Boise, Idaho-based Peregrine Foundation provides much of the funding for the condor program.
Earlier this year, one condor was returned to captivity after hanging around a resort parking lot, approaching river rafters and watching planes.
But the risk of condor-human interaction should begin to taper off, Humphrey said.
''At a young age they are very curious of humans, but as they find there is no positive reinforcement, they get bored with humans,'' he said.
To make sure that happens, the Peregrine Foundation has distributed 9,000 brochures at the Grand Canyon, discouraging people from getting close to the large birds, he said.