Learning to be wild
The lost language of cranes
Wanna see some movies?
Crane chicks being fed.
Crane chicks sparring with each other.
(2.8MB, QuickTime).
Cranes following their keeper.
(1.2MB, QuickTime).
Cranes learning to fly.
(.7MB, QuickTime).
Courtesy of the International Crane Foundation and Dave Erickson.
The quest to breed the endangered whooping crane in captivity nearly foundered on the very imprinting problem that Konrad Lorenz discovered.
When George Archibald, director of the International Crane Foundation, tried to breed his first whooping crane, the bird would not perform the breeding dance with fellow cranes because it was imprinted on people.
Archibald explains that cranes, like most birds, "learn to recognize their species by seeing their parents" just after birth. It's just the way of nature. But if those parents are Homo sapiens, then the cranes believe humans are their parents.
Since each whooper's genes are valuable to a worldwide population that plummetted to 15 in the 1940s and still numbers below 300, Archibald learned to dance with Tex, as he named the mis-imprinted would-be mother bird. It took a lot of time, and made Archibald look a trifle foolish, but it did succeed in hatching a new whooper in 1982 through artificial insemination.
Important imprinting
Having learned an expensive lesson on the power of imprinting, the Foundation now goes to great length to ensure that cranes destined for return to the wild can recognize their fellow cranes. "We have to keep them completely isolated from humans who don't wear [crane] costumes," says Archibald. The young are fed with a bogus crane beak. 
Tapes of crane noises, like the soft purrs of brooding parent cranes, play in the rearing houses. Humans stay out of sight and speak only in whispers.
Crane chicks being fed. (4.5MB, QuickTime movie).
When the birds are old enough to go outdoors, tenders don their hot, floppy crane costumes (cranes flock to their parents, even those that happen to be cloaked in absurd outfits). The tenders spend lots of time in the water, teaching cranes that it's safer to roost on water than on land, where cranes are vulnerable to bobcats and other mammals that scoff at endangered species laws.
The crane raisers have no truck with the warm fuzzies that Jessie shared with Willy the killer whale. Instead, preparation for life in the wild includes being harassed by uncostumed humans, to teach the elegant birds to fear this two-legged predator.
Nurture-- or nature?
Wouldn't these stalky birds do better if, for example, they instinctively sought wet roosting areas, safe from predatory mammals? Apparently not. This ability to learn, sometimes exalted as "brain plasticity," allows cranes to learn on the job. "If they were programmed to do everything they do, and the environment changed, they would be stuck," says Archibald, one of the world's leading experts on cranes. "Because they have to learn, and learning may continue through the lifetime, they have greater plasticity to adapt to the environment."
One thing that cranes can learn to trust is an ultralight airplane. Say what?
Cranes, as we've seen, must learn to recognize their own species, but they do have some innate skills as well, Archibald says. "For cranes, the things that are genetically acquired are displays [for courting, marking territory, or attracting mates] and vocalization, which is not altered no matter how they are raised." Aside from recognizing their parents, cranes must also learn roost locations, migration pathways and species orientation. "It's very important that during the first 10 months they learn all this stuff," Archibald adds.
