“The whooping crane is doomed to extinction,” the noted ornithologist Edward Howe Forbush predicted flatly in the early 1900s – and there was precious little to suggest otherwise.

This magnificent bird – tall as a man and white as a snowdrift, with inky wingtips and a splash of crimson on the crown – had once nested from the Canadian parkland to the tallgrass prairies of the upper Midwest and perhaps as far east as the Carolinas. In winter, its brash, trumpeting call could be heard from the Chesapeake south to the Gulf Coast and Florida. But reckless gunning had reduced the cranes to a pitiful few dozen by the 20th century, and even with the dawn of wiser policies toward endangered species, the whooper teetered on the brink.

But George Archibald never bought that gloomy assumption. “I’m an optimist,” Archibald says simply. As a PhD student at Cornell in the 1970s, the Nova Scotian began working with cranes, many species of which were close to extinction.

“I knew that if you did the right thing with the birds in captivity, you could produce a ton of cranes,” Archibald said. So in 1973, he and a fellow Cornell student named Ron Sauey founded the International Crane Foundation in Baraboo, Wisconsin.

Doing “the right thing” meant, among other things, leaping and dancing like a male crane to bring a human-imprinted whooper named Tex into breeding condition, then using artificial insemination to allow her to raise a chick – a huge step for a species that then numbered barely a hundred birds.

Today, Archibald is universally recognized as the world’s foremost authority on cranes. And while whooping cranes have edged away from the brink that seemed so imminent to Forbush – there are now nearly 540 birds in several wild and captive flocks – even the optimistic Archibald cautions that they aren’t out of the woods.

The original wild flock – which nests in remote Wood Buffalo National Park in the Northwest Territories and Alberta, and migrates 1,200 miles south to Aransas National Wildlife Refuge on the coast of Texas – reached a record 266 cranes last year. A nonmigratory flock of about 30 cranes, established in 1993, lives in central Florida, and the ICF, working with partners including the U.S. Fish and Wildlife Service and Operation Migration, has also created a flock of more than 90 whoopers that migrate between Wisconsin and Florida (with ultralight planes leading a fresh batch of chicks south every autumn).

But all these cranes, crisscrossing the continent, reinforce the urgency behind Patagonia’s Freedom to Roam campaign – that without safe corridors along which to travel, the world’s most iconic wildlife migrations will wither; that without interlocking, protected habitat weaving together our natural communities, plant and animal populations won’t be able to shift their ranges in response to accelerating climate change.

Each of the whooping crane flocks faces its own challenges. The migratory eastern population has suffered from inexplicable breeding failures in Wisconsin, while in Florida, water shortages and continuing habitat loss have badly hamstrung the dwindling nonmigratory population.

Even the burgeoning Wood Buffalo/Aransas flock is under growing pressure, Archibald cautions. “One of the big chokepoints is coastal development in Texas and the siphoning of inflows of freshwater from the Guadalupe River into the marshes at Aransas.” Marshes are being gobbled up for housing developments, and the river water that keeps the salinity of the estuaries perfect for blue crabs – the whoopers’ main food there – is being diverted to urban centers like San Antonio.

Getting to and from the coast is increasingly hazardous, too. “The major cause of mortality in whooping cranes is collision with power lines on their 1,200-mile migration between Canada and Texas,” he said. “This is the Great Plains, and it’s also the Great Wind, and farmers that were failing agriculturally are lining up to lease their land for wind farms.”

“Cranes, as far as we know, aren’t killed by turbines, but the wind farms require thousands of miles of new power lines right in the middle of their migration route,” he warns. Because whooping cranes don’t stop at traditional places each year on their migration, Archibald says that it’s impossible to know where conflicts will arise. Even if you keep the lines away from every marsh and prairie pothole where they might roost, the cranes also fly to agricultural fields to feed. Each new wind turbine, each mile of new electrical line, is a potential hazard, turning this crucial migration pathway into a game of aerial roulette.

Yet the man who danced with Tex remains remarkably sunny about the whooping crane’s long-term chances. He and his colleagues are working on plans to create still other migratory flocks, perhaps reconnecting the prairies of southern Manitoba with the coastal marshes of Louisiana, where the great birds once thrived. This would link again far-distant landscapes through flight and movement, and bind up the severed flyways of the continent with the annual passage of white birds, trumpeting loudly from the clouds.