MIAMI — MIAMI -- The fate of a generation of endangered migratory whooping cranes now rides on the fragile wings of a 10-month-old chick known as No. 15.
He is the sole survivor of the Class of 2006, 18 crane hatchlings that followed four costumed ultra-light aircraft from Wisconsin to Florida wintering grounds in December as part of a project to introduce a second migrating population to North America.
Conservationists with Operation Migration had originally feared all of the brood had perished in the storm that killed 20 people in central Florida on Friday and put hundreds of residents from their homes.
But No. 15, a male chick, managed to break loose from a top-netted pen Friday when deadly tornadoes struck and killed his 17 flock mates.
A bracelet-like radio transmitter attached to the crane's leg sent out signals over the weekend, said Joan Garland of the International Crane Foundation in Baraboo, Wis.
Just before nightfall Sunday, an aerial search team of ICF volunteers spotted No. 15 safely amid a flock of sand hill and older whooping cranes in the Chassahowitzka National Wildlife Refuge on the swampy Gulf Coast, about 90 miles north of Tampa.
"What a bright spot he is in this sad time," said Joe Duff, a founder of Operation Migration and one of the ultralight pilots who guide each year's brood from their summer habitat at the Necedah National Wildlife Refuge in central Wisconsin.
"We've lost a whole generation."
Scientists and wildlife conservationists dedicated to preserving the birds that numbered only 15 in 1940 try to stay aloof from their wards. They refrain from naming the birds to reinforce the idea that they are not pets but wild creatures, said Duff.
"Still, you get attached," he said.
No. 15 and his 2006 classmates were a story of success against all odds.
A snowstorm a year ago disrupted breeding at Maryland's Patuxent Wildlife Research Center for a month. Despite the late hatching and return of the fledglings to Wisconsin, Operation Migration managed to get a flock of 18 trained in time to trail the ultra-lights on the trip south that started in October.
Inclement weather along the migration route slowed the birds' journey to Chassahowitzka from the usual 50 days to 78, yet all 18 made it there safely.
No. 15 dropped out on the last leg of the journey but was spotted two days later and reunited with the flock.
Then Friday's tornadoes wiped out a year of work to bolster the cranes' population, which numbers fewer than 500 across North America and only 64 now in the Wisconsin-Florida flock.
Wildlife biologists aren't sure exactly how the birds were killed. They suspect a lightning strike during the ferocious weather that raged across central Florida before dawn.
Or the birds might have been drowned if trapped by the net during a storm surge brought on by 165-mph winds, Duff speculated.
The crane carcasses have been sent to the University of Florida at Gainesville for necropsies to be carried out with a grant from the Disney Wildlife Conservation Fund, said Jim Kraus, the Chassahowitzka refuge manager.
He said the conservationists might rethink the practice of covering the newly arrived chicks' territory with netting.
Fight for food
Crane foundation monitors at the refuge feed the first-timers pellet food until they learn to forage for themselves. But older cranes in the refuge began harassing the younger ones to get at their food, which prompted project organizers a couple of years ago to extend netting over the youngsters until they were strong enough to be released into a larger, uncovered 5-acre pen, said Garland.
The 17 that died Friday were within a few weeks of graduating from the covered pen, which is only about 150 feet wide, she said.
Being the only survivor of his generation shouldn't affect No. 15's breeding potential, the crane advocates said.
Generally monogamous, whooping cranes don't mate until they are about 5 years old and often pair off with a bird from a previous or subsequent generation.
"He's been led on migration once, so he has an idea where he's going," Duff said of No. 15. "I expect we will see him in Wisconsin in the spring."
Carol J. Williams writes for the Los Angeles Times.