The remoteness of the 17,298-square-mile wilderness, set aside in 1922 for Canada's last wood bison, has aided the cranes. Here whoopers 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 fish. "Wood Buffalo is and always will be truly wild," says Tom Stehn. "The 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 flights over several months—59 hours in the air—to finish one season's count of 62 nests, 52 chicks, and 22 fledglings 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, killing the crabs that cranes eat in winter. That 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 flyway. "The best wind flows 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 fivefold before bird advocates can truly rest. But veterans of the effort 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 finally leave the cranes alone."
Come October, the cranes at Wood Buffalo 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 aloft. 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 off.