PATUXENT RESEARCH REFUGE, MARYLAND--Wildlife biologists are teaching one of the United States' most endangered species a weird game of follow-the-leader. It's for the whooping cranes' own good--the captive-reared birds need to know where to breed and how to migrate south during the winter, and an ultralight airplane is going to show them the way. This morning, during a test run, a person dressed up as the world's most graceless crane led hungry crane chicks around in circles behind the plane.
Whooping cranes are sensitive birds. They need big wetlands and plenty of time; most don't breed successfully until they're 6 or 7 years old, and even then only fledge one chick every 2 years. In the 19th and early 20th centuries, people hunted the big birds for meat and feathers. By 1941, only 21 birds remained. To boost the population, researchers here established a captive breeding program in 1965, since then introducing 86 human-reared birds to a preserve in Florida. Another wild population, which breeds in Canada and winters in Texas, has grown to 176.
Biologists would now like to establish a third population, to reduce chances that a single virus, hurricane, or oil spill will wipe the species out entirely. If all goes well, that population will breed in Wisconsin and winter in a second preserve in Florida. But first the birds need to learn how to get from one place to the other.
To teach them the route, biologists here have been training 10 chicks, all younger than 2 months old, to follow the aircraft. Not yet able to fly, the chicks hopped around desperately during the demonstration this morning, chomping up mealworm pellets dropped by their costumed trainer. To keep the chicks from learning that humans mean a free meal, the trainers dress up in a flapping white sheet and hold out a long "robocrane" appendage that looks like a crane neck and head. The chicks already know that the stuffed and wired head will feed them; they're also learning that "mom" sounds like an engine and has a huge propeller on her backside. In a few weeks, the cranes will be shipped to Wisconsin, and from there the plane will lead them to Florida.
"When I first heard about the idea, I thought it was pretty far-fetched," says Tom Stehn of the U.S. Fish and Wildlife Service, who manages the wild flock of cranes at the Aransas National Wildlife Refuge in Austwell, Texas. But a test flight in 1997 with adult cranes showed that they take advantage of the ultralight's turbulence to hitch an easy ride. If the third population starts breeding and migrating on their own--probably in 10 years' time--and the total population reaches 1000 birds, the whooping crane could be taken off the endangered species list.
--LAURA HELMUTH
Related sites
The Whooping Crane Reintroduction Project
The Whooping Crane Eastern Partnership
Operation Migration, the folks with the ultralights
