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Scientists Work to Increase Whooping Crane Population

Some famous whooping cranes are back in the American Midwest after spending the winter in the southern state of Florida. The cranes are part of an experiment aimed at increasing the number of whooping cranes, which is an endangered species. Wildlife experts say they're happy with how the project is going, but several changes in the whooping crane recovery plan are in store.

Scientists from both the public and private sectors are trying to create the first migrating flock of whooping cranes in the eastern U.S. in more than a century.

Last year researchers got eight young birds to follow ultra-light aircraft. The planes led the endangered whoopers on their first migration this past fall, from Wisconsin to wintering grounds in Florida. Scientists say they were pleased when five of the cranes flew back on their own this spring to the Necedah National Wildlife Refuge. The return flight was just one way the eastern cranes have shown they behave like other wild whoopers, said Necedah manager Larry Wargowsky.

"They would raise up to altitudes of [about 1,500-1,800 meters] using thermal currents, ... then glide down to lower elevation then climb back up and glide," he said.

But the apparent initial success of the project isn't leaving wildlife biologists sitting on their tail feathers. Scientists will monitor the yearling birds as they fly on and off the protected Wisconsin refuge this summer. Jim Harris of the International Crane Foundation, based in Baraboo, Wisconsin, says the whoopers are exploring nearby farm fields to eat waste corn. Happily, Mr. Harris says, the birds are also trying out local wetlands. "Last year, we gave them a fair amount of exposure to water, but we want to increase and encourage that attraction to water especially for roosting," he added.

Mr. Harris says the more the cranes stay away from dry brushy areas, the less susceptible they are to predators like gray wolves and coyotes. Because the young cranes are too immature to breed, the scientists are also preparing for another batch of crane chicks to be brought in from a wildlife center in Maryland. The whooping crane recovery team expects about 20 chicks to come in - double last year's number - so the team is already preparing additional training space at the Wisconsin refuge. Jim Harris says the new chicks need to train with costumed humans and ultralight aircraft, just like the first group did, and he hopes the yearling cranes don't interfere.

"Among other things, the older birds might be aggressive toward the younger ones. They certainly would be a distraction," he said. "We're trying to teach the young birds to follow right behind the ultralight and if larger birds were there jostling for position or trying to be near the aircraft that could disrupt things."

Mr. Harris says he also hopes the flight training will start earlier this summer than it did last year, so to finish before the early fall winds in Wisconsin become too strong.

Last October, during the southerly migration, one bird was found dead near a power line after the crane got loose during a windstorm. Beth Goodman of the Wisconsin Department of Natural Resources says scientists do not want a repeat of that. "We have made changes to the travel pen the birds stay in at night, so if there is another windstorm we don't anticipate the pen will blow apart," she said.

Ms. Goodman and others are also looking ahead to next winter in Florida. The researchers are planning some changes to help improve water roosting sites. The cranes stayed on higher and drier ground this past winter and that enabled Florida bobcats to kill two of the birds.

So far, the whooping crane recovery project has cost almost $2 milllion, but scientists say the intensive attempt to bring back an endangered species is well worth it.