National Geographic : 2010 Jun
• farms and shot birds for meat. When a major storm in 1940 led to the petering out of a ock in Louisiana, at most 22 wild whoopers remained. e bird has become the emblematic endan- gered species, thanks in part to its erce charisma. Standing nearly ve feet tall, it can spy a wolf---or a biologist---lurking in the reeds. It dances with springing leaps and flaps of its mighty wings to win a mate. Beak to the sky, it fills the air with whooping cries. e sole wild ock, listed under the Endangered Species Preservation Act in 1967, has slowly expanded. At the same time, conservationists have hatched and bred the birds in captivity and reintroduced them to their for- mer habitat, boosting the total---including cap- tive stock---to more than 500. To rescue this darling among the world's 15 crane species, scientists rst needed to answer a burning question: Where did whoopers nest--- and lay eggs---in summer? Since the late 1890s biologists had known that the wild ock win- tered on coastal marshland in what would later become the Aransas National Wildlife Refuge in Texas. To crack the summer mystery, o cials asked citizens to report sightings; volunteers combed the migration route for clues. en, in the summer of 1954, a report came from a re helicopter ying over a virtually inaccessible wetland some 2,500 miles north of Texas, on northern Canada's boreal plains. A whooper family was on the ground. By lucky chance, the ock had settled inside Wood Bu alo, the big- gest national park in North America. e remoteness of the 17,298-square-mile wilderness, set aside in 1922 for Canada's last wood bison, has aided the cranes. Here whoop- ers face only natural predators---wolves, bears, foxes, egg-stealing ravens---as they guard two-square-mile territories, nest hock-deep in water, and raise one or sometimes two chicks on a diet including insect larvae, seeds, snails, and sh. "Wood Bu alo is and always will be truly wild," says Tom Stehn. " e birds are safe here." Back overhead, the red plane dips to the west as Craig-Moore excitedly calls out another sighting. Even with GPS coordinates from past surveys, it will take multiple ights over several months---59 hours in the air---to nish one sea- son's count of 62 nests, 52 chicks, and 22 edglings spread over 100 square miles. As of February 2010, the cranes' annual tally sat at 263. So they are holding steady---but remain at great risk. In Texas, water diversion for farms and suburbs is boosting salinity in coastal salt marshes, kill- ing the crabs that cranes eat in winter. at land is already vulnerable to storms and rising seas. Lost wetlands, oil sands development in Alberta, and wind power projects also mean fewer resting spots on the yway. " e best wind ows along the migration route," says Stehn, "and there are plans to erect thousands of turbines." Windmills themselves may not present major obstacles, but power lines will. "It shows how fragile a success story this is." Today's population must expand at least ve- fold before bird advocates can truly rest. But vet- erans of the e ort are optimistic about reaching that goal. Says CWS biologist Brian Johns, "With enough habitat protection, in a couple of decades maybe the population won't need us anymore. Maybe we can nally leave the cranes alone." Come October, the cranes at Wood Bu alo prepare for an ancient ritual, the weeks-long journey to their Texas wintering grounds. Strutting across the spongy earth, an adult male tilts his head, one yellow eye peering skyward, waiting for his weather cue: The arrival of thermals that will carry his family alo . As the air begins to shimmer, he leans his long body forward, signaling his intention. His mate and young quickly copy the posture. And then, in near-perfect unison, they take o . j "With enough habitat protection," says biologist Brian Johns, "in a couple of decades maybe the population won't need us anymore."