The aerial census takers are Bredy, Tom Stehn of the U.S. Fish and Wildlife Service, and Lea Craig-Moore of the Canadian Wildlife Service (CWS), and they're worried. The flock's population had reached 266 in the spring of 2008. But by the following spring, 57 had died, 23 of them on the birds' wintering grounds in south Texas, where drought had decimated their main food—blue crabs and a plant called wolfberry. Others probably perished during migration, often after striking power lines, the biggest known killer along the flyway. The higher-than-average death count has added urgency to a new effort that tracks some migrating birds with GPS anklets.
Still, whoopers, as they're called, aren't nearly as bad off as they once were. A key event in their revival took place 42 years ago, when CWS biologist Ernie Kuyt went on a spring treasure hunt. A helicopter let him off on the soggy boreal landscape, a vast expanse of sedge meadow and ponds broken up by islands of black spruce and willow. Using a jack pine pole as a staff, he trudged through muck that might have stolen his resolve—and his boots. At the heart of a shallow pool, he spied a massive nest cradling a pair of blotchy eggs, each the size of an Idaho potato. Kuyt had left his container in the copter, so he tucked a sole egg into a wool sock, sensitive to the weight of the future life—and the possible salvation of a species—he'd carry home.
Kuyt's excursion marked a major step in the now decades-long effort to save the whooping crane, begun by the National Audubon Society's Robert Porter Allen and others in the 1940s. The egg in Kuyt's sock helped seed the captive-breeding program that is crucial to the species' rescue. Multiple flocks once crisscrossed the continent, but numbers fell drastically in the mid-1800s as settlers converted wetlands to farms and shot birds for meat. When a major storm in 1940 led to the petering out of a flock in Louisiana, at most 22 wild whoopers remained.
The bird has become the emblematic endangered species, thanks in part to its fierce charisma. Standing nearly five 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. The sole wild flock, 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 former habitat, boosting the total—including captive stock—to more than 500.
To rescue this darling among the world's 15 crane species, scientists first 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 flock wintered on coastal marshland in what would later become the Aransas National Wildlife Refuge in Texas. To crack the summer mystery, officials asked citizens to report sightings; volunteers combed the migration route for clues. Then, in the summer of 1954, a report came from a fire helicopter flying 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 flock had settled inside Wood Buffalo, the biggest national park in North America.