Sometimes nature does what we expect. Other times, events remind us that “wildlife management” can be an oxymoron.
For partners and national wildlife refuges working to bring endangered whooping cranes back from near–extinction, 2011–2012 was a winter when the weather—and the big birds themselves—called the tune.
Typically most of North America’s migratory whooping cranes winter in one of three places: Aransas National Wildlife Refuge in Texas, the customary winter home of the wild, naturally migrating western flock; or Chassahowitzka and St. Marks Refuges in Florida, chosen by the Whooping Crane Eastern Partnership as wintering sites for the mostly captive–born eastern flock.
But in January, four times more eastern whooping cranes were in Indiana (40) than in Florida (10). Wheeler Refuge was hosting unexpected guests: nine juvenile whooping cranes that were migrating behind an ultralight when they stopped near the Alabama refuge and would fly no farther.
And while most of the western flock made it to Aransas Refuge, groups of whooping cranes were confirmed in Oklahoma; in Kansas, where a Dec. 26, 2011, sighting at Quivira Refuge was the latest on record; and in Nebraska, where cranes were seen on the Platte River in January.
No one knows why the cranes splayed out across the continent’s midsection. But experts think they took advantage of a warm winter, staying wherever they found ice–free roosts and food.
“It was just a weird winter,” said St. Marks Refuge manager Terry Peacock, a member of the Whooping Crane Eastern Partnership rearing and recovery team. St. Marks Refuge had been the first Florida stop for the Operation Migration ultralight and its Wisconsin–reared cranes. But when this year’s flock wouldn’t budge from Alabama, the team changed the destination to Wheeler Refuge.
Whooping cranes are most loyal to their nest sites, Peacock said, and the young birds must make that return journey on their own in spring. By halting the whooping cranes at Wheeler Refuge, the team hoped to help them make it safely back to
Wisconsin, she said. “It was disappointing for us, but we knew it was the best thing for the birds.”
Over the past decade, Wheeler Refuge has become a crane magnet, with thousands of sandhill cranes and several adult whooping cranes overwintering there, said refuge manager Dwight Cooley.
“The cranes have picked this place out on their own, so it’s obviously got what they need,” said Operation Migration wildlife technician/pilot Brooke Pennypacker. The refuge closed a popular trail to create a nighttime roost, but by day visitors could see the whooping cranes from an observation tower.
“This has worked out very well,” Pennypacker said in April, just days before the young birds headed north.
The worst drought in Texas history caused some western whooping cranes to stay north or spread out along the Gulf Coast, said Aransas Refuge manager Dan Alonso.
In January, refuge marshes were as salty as seawater, driving blue crabs, a staple of the cranes’ diet, into deep water where they were unreachable. Refuge staff burned 13,210 acres to create new feeding grounds and re–conditioned 10 abandoned windmills and stock ponds to provide drinking water.
Aransas Refuge surveys peaked at 245 birds, compared to 281 in 2010–11, but Alonso said the cranes’ dispersal and a new survey protocol means the numbers aren’t comparable.
“Although this was a harsh year, these are the conditions under which these birds evolved,” he said.
The eastern flock’s tally of 107 birds was close to last year’s, but biologists couldn’t locate 15 of them in early April.
Still, “it’s good to see that the birds can respond to changing conditions, and that we have good conditions for them throughout the Southeast,” said Bill Brooks, a U.S. Fish and Wildlife Service wildlife biologist working on whooping crane recovery. “They’re showing us that the habitat can support a larger population.”
Heather Dewar is a writer–editor in the Refuge System Branch of Communications.
