Whooping cranes

Wednesday, March 2, 2016

Christopher Joyce / NPR

Biologists hoping to bring endangered whooping cranes back from the brink started an experimental flock in 1967 at the U.S. Geological Survey's Patuxent Wildlife Research Center in Laurel, Md.

When a whooping crane stands up, you notice. At 5 feet in height, it's America's tallest bird. Its wingspan is more than 7 feet, its body snowy white, its wingtips jet black.

By the 1940s, the birds had nearly gone extinct. Biologists have worked hard to bring them back, by breeding whoopers in captivity and releasing them in the wild. There are now several small wild populations in the U.S.

Perhaps the most remarkable is the eastern group. For 15 years, biologists have been teaching some of the young cranes to migrate between Wisconsin and Florida by leading them with an ultralight, one-person aircraft.

Now, however, biologists have discovered that teaching the cranes to migrate seems to have created serious problems for the birds — they rarely reproduce successfully. The Federal Fish & Wildlife Service has halted the flights and is now trying to figure out what went wrong.

The irony here is that the migration project, a leap of faith and a scientific gamble, worked.

It was a terribly difficult experiment. Biologists breed the birds at the Patuxent Wildlife Research Center in Laurel, Md. Every person involved wears a long white coat and a hood. They even wear phony beaks. The aim is to keep the young birds from imprinting on people — seeing their human caretakers as parents. Instead, the researchers want the birds to consider the ultralight aircraft and its pilot, also costumed like a bird, as their leader. To that end, while still very young, the whooping cranes are introduced to the plane on the ground and encouraged to follow it and its pilot around.

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