To Make A Wild Comeback, Cranes Need More Than Flying Lessons

AUDIE CORNISH, HOST:

When a whooping crane stands up, you notice. At five feet, it's America's tallest bird. Its wingspan is more than seven feet. Whooping cranes almost went extinct, but biologists bred them in captivity. And for years now, they've been trying to reintroduce them into the wild. But as NPR's Christopher Joyce reports, scientists have run into some unexpected problems.

CHRISTOPHER JOYCE, BYLINE: Joe Duff calls himself an avian aviator. For years, he's been flying his one-man, ultra-light aircraft alongside whooping cranes that have been bred in captivity. He teaches them how to migrate between Wisconsin and Florida. The young birds follow him because they think he's an adult crane. This spectacle draws crowds of craniacs (ph), who follow the migration and videotape Duff and the snowy white birds as they fly overhead. But Duff says videotape can't begin to capture the feeling of actually flying with these huge birds almost within arm's reach.

JOE DUFF: When you have this bird with an eight-foot wingspan right off your wingtip, you know, and you're a thousand feet up and they're all around you, it's just - you know, the sun is shining on them

JOYCE: Duff is a burly, dark-haired Canadian who grew up wondering the north woods. Biologists approached him 15 years ago and said, we've bred a few eastern whooping cranes in captivity. Now, we want pilots to teach them how to migrate so that they can be real wild whooping cranes again. It was called Operation Migration.

DUFF: Oh, it's changed me completely. It's just spectacular to watch a creature like that. I mean, their species has been migrating for millions of years.

JOYCE: It was a terribly hard experiment, though. Biologists breed the birds at the Patuxent Wildlife Research Center in Maryland. Every person involved wears long, white coats and hoods. They even wear phony beaks. The aim is to keep the birds from imprinting on humans. They want the birds to consider the ultra-light aircraft and its pilot as their leader.

DUFF: You become, actually, part of their social structure. You're the dominant bird. You're the parent bird within the flock.

JOYCE: But this February, the U.S. Fish and Wildlife Service canceled the project. Yes, the birds did learn to fly the eastern migration - about a hundred of them do it now on their own - but migrating wasn't the problem - reproducing was. I went to Patuxent to find out what happened. I walked through snow and up a flight of wooden stairs to a shack - a bird blind. Through an open window, I could see leggy whoopers standing elegantly in fenced-in enclosures - and hear them.

SARAH CONVERSE: They're good looking bird, aren't they?

JOYCE: Patuxent biologist Sarah Converse helps breed the whoopers. She was exhilarated to see them actually migrate, but devastated to discover that once they arrived at their breeding grounds in Wisconsin, they just didn't breed well on their own.

CONVERSE: We have two separate problems. One, the eggs don't make it. Two, even if the eggs make it, the chicks don't make it.

JOYCE: The cranes mate OK, but fewer than 1 in 10 reproducing pairs actually raises a chick that lives more than four months.

CONVERSE: It's not like we're almost there with reproduction. We're not really anywhere close. And so it sort of suggests that there's something wrong with the birds and the way they behave.

JOYCE: They may not be staying with the eggs long enough, or they don't know how to protect the eggs or the newly hatched chicks from predators. But then, how would they know? John French, the biologists who runs the crane program at Patuxent, isn't terribly surprised that the captive-bred birds are confused. They were raised by humans, and even if the humans wear white robes and beaks and fly with the birds, they're still humans.

JOHN FRENCH: It's a very odd experience for the bird. They would never do that in the wild. And we really don't know how that affects the bird

JOYCE: So after 15 years, the scientific team has stopped the flight training. It requires too much interaction between chicks and humans and not enough with their avian parents. The biologists fear the chicks are missing some lesson about how to be good parents themselves. Or, says French, captive-bred birds may become genetically different from birds in the wild and lack some crucial gene for good parenting. Whatever the case, French says it's a lesson on how difficult it is for people to re-create something that took millions of years of evolution to make.

FRENCH: I think we're finding out that the ark that we've built, you know, might not be the best way to preserve them, or we might have to think of a different kind of ark. Our goal here now is to step back as far as we can from that human-bird interaction and allow the bird to, you know, develop as a bird.

JOYCE: So now, the chicks will stay with their parents in Patuxent for their first year, then they'll be transported to their breeding sites in Wisconsin, and nature will take its course. As for migrating back south, there are enough mature birds now to teach the newbies the flight path. As for Joe Duff and Operation Migration, the end of his career as an avian aviator is hard to take, especially his last flight with the cranes, February 6. The wind was too strong to fly, but he tried anyway and got forced down. He wrote this about the end of the project and that last flight.

DUFF: I mean, it's the proper thing to do, but somehow it should have ended differently. There should have been clear skies, a colorful sunrise, a string of courageous birds off my wingtip. But nature doesn't work that way, and I should have known better.

JOYCE: Christopher Joyce, NPR News. Transcript provided by NPR, Copyright NPR.