Researchers retool effort to restore crane population
Twenty-five miles south of Baltimore, in a grassy pen enclosed by two rows of fences, electrified to provide protection against raccoons and monitored by video cameras, a pair of the tallest birds in North America emerge from their hut.
Powder-white, all neck and legs, they step through the rain with care, as if in high heels.
For 15 years, staff
But something was wrong.
Once released in the wild, the stately birds
It turned out they couldn't teach parenthood.
“We still can't do better than Mother Nature,” said Brian Clauss, the flock manager.
In January, federal wildlife officials decided to end the theater. They scrapped the ultralight-led migrations and scaled back the costumed rearing of chicks “to put emphasis on more natural methods of rearing and releasing whooping cranes,” the
Now spring approaches, and with it the first eggs will be laid in a popular experiment that's changed course.
The whooping crane project has been described
Whooper home
The Patuxent refuge — nearly 13,000 acres of marsh and woodlands
Signs of its history linger today, such as the fenced plots where earthworms tested positive for DDT decades after the pesticide was applied. In 1969, Patuxent researchers linked DDT to the thinning of birds' egg shells, a discovery that led to the pesticide's ban to protect bird populations.
The first whooping crane, a one-winged male named Canus, arrived in 1966. When he was rescued, the U.S. Geological Survey says, he was one of only 42 whooping cranes left in the wild. Named for the cooperation between Canada and the United States to save the species, Canus went on to sire many of the whooping cranes hatched in captivity.
Breeding efforts expanded in June 2001 with the whooping crane reintroduction project.
The U.S. Fish and Wildlife Service launched the project to raise and train a new population of cranes to be released into the wild for migration
Success would be a milestone in wildlife conservation: There has never been a successful crane reintroduction, said Peter Fasbender, the lead Fish and Wildlife Service biologist on the project.
Soon came documentaries, fan clubs, even “wild for whoopers” swag.
Whoopers are white with black wingtips and yellow eyes.
Whooping cranes mate for life. When breeding, the male climbs on the female's back and flaps for balance. So clipped wings mean birth control.
As many as 20,000 whooping cranes roamed North America before humans interfered, according to the National Wildlife Federation. Their white feathers became high fashion in women's hats. They were targeted by commercial hunters and sold for meat. Wetlands were drained. Power lines were raised. A 1941 count found
In February last year, the Fish and Wildlife Service counted 603 whooping cranes. But they
At Patuxent, it worries Clauss how closely the chicks follow him. He's afraid of stepping on one.
“It's a little precarious in the beginning,” he
Whooping cranes typically lay two eggs at a time. Steal the eggs, and they lay two more. In this manner, researchers can coax six eggs from a pair.
That's too many chicks for the pair to raise. Also, siblings fight. The stronger chick
So each spring at Patuxent, Clauss and several other “crane technicians” become surrogate parents to about 30 chicks. They
“When it does see a human after it's released, it will be afraid,” Clauss said.
At hatching, the birds are 5 inches tall and gangly. Clauss
To teach drinking, he splashes the puppet beak in a water dish. The chick imitates.
For eating,
He leads them on walks; they follow at his boots. He intervenes in fights and soon they outgrow their hostility.
“You're trying to shape their little minds,” he said. “It's a big responsibility.”
Next, the chicks are introduced to ultralight airplanes. Costumed pilots drive a grounded plane around a pen. A mechanized puppet head drops mealworms as the chicks follow.
Come fall, the young cranes are crated and flown to swampy Necedah National Wildlife Refuge in Wisconsin. Then they fly behind the ultralight to refuges on Florida's Gulf Coast. After one trip, they remember the route and migrate unassisted the next year. Planes lead only each new class of cranes.
The January decision changes it all.
“We're no longer going to do the ultralight release,” said Sarah Converse, a research ecologist at Patuxent. “We're also moving away, to the greatest degree possible, [from] any costume rearing.”
Problems surface when the grown chicks mate in the wild.
Some abandon their eggs. Others abandon their chicks. Alone, the offspring are eaten by crows, snakes and raccoons.
What's broken?
So the whooping crane reintroduction project presents a troubling question: What's broken in the cranes?
Swarms of black flies are driving some birds from their nests, but researchers suspect a deeper problem.
“There's something about these birds' early-learning experiences that affects their breeding,” Converse said. “For example, you're cared for by your parents and you learn something that we can't really teach because we don't know it. It would take us a long time to understand the intricacies.”
Over the years, Patuxent researchers searched and studied, but failed to pinpoint the missing lesson. Since the project began in 2001, the researchers have released
“We're meaningfully far from where we need to be,” Converse
Federal wildlife officials say the reproductive failure was reason
The decision was reached at a meeting in Wisconsin of the Whooping Crane Eastern Partnership, a group of federal and state agencies and nonprofits working to restore cranes.
Nearly 100 cranes migrate from Wisconsin to Florida each year, but they fail as parents. The partnership's goal is to build a self-sustaining flock.
“While survival of the birds is something we are proud of, a critical lack of reproductive success has hampered the partnership's effort to meet its goal,” the partnership
Two other flocks exist. About 40 cranes live year-round in Louisiana. Another 300 migrate from Canada to the Gulf Coast of Texas.
That
“That's why people worked so hard to introduce another population,” Converse said.
Without airplanes, puppets or costumes, captive cranes at Patuxent will raise their own chicks until fall. Then juveniles will be shipped to Wisconsin to follow other migrating cranes.
The researchers say the
So researchers are betting these fewer chicks will grow to be better parents.
They say it will take five years before they know.