Whooping cranes to be sent into wild Some of rare birds were bred in Md.

January 04, 1993|By Bernice Wuethrich | Bernice Wuethrich,Contributing Writer

Whooping cranes raised in captivity in Maryland and Wisconsin will be the first whoopers bred by man to be sent into the wild when a dozen are released this week on the meadows of Florida.

The 12 whooping crane youngsters -- bred at the Patuxent Wildlife Research Center and the International Crane Foundation in Baraboo, Wis. -- are set to emerge from their wooden crates onto Kissimee Prairie Wednesday.

The wild flock of whooping cranes, which numbered 14 a little more than a half-century ago, has grown to about 135.

"The release is a fantastic experience for me," said Dr. George F. Gee, a Patuxent research physiologist who has worked with a captive flock since 1968, when the cranes were declared endangered. "It is the fruition of a tremendous dream."

The Florida release is the first effort to use captive-reared whooping cranes to start a wild flock.

The Patuxent center in Laurel is the oldest and largest research facility of the U.S. Fish and Wildlife Service.

There, young whoopers are bred in huge pens set amid forests of maple and ash, ponds thick with waterfowl and herds of white-tailed deer.

Standing 5 feet tall when mature, whooping cranes are North America's tallest bird.

Their snow-white wings, tipped with arrows of obsidian black, span 7 feet. With their long legs and necks, the birds move with an undulating grace.

They were once abundant along the Atlantic seaboard, and their range extended from Mexico through the Great Plains and Rocky Mountains and into northeastern Canada. Their population plummeted to the brink of extinction 50 years ago, and at their low point in 1941 only 14 existed.

The last wild whooping crane was seen in Florida in 1937, when it was shot from the sky by a hunter.

Efforts to reverse the slide involved habitat protection and captive breeding, a project that has involved governments in the United States and Canada, the National Audubon Society and thousands of citizens.

Critical land areas used by the 14 remaining wild birds were protected; a wintering reserve was set aside in Aransas, Texas; and in Canada a safe summer breeding ground was ensured at Woods Buffalo National Park.

The flock of 135 in the wild is considered precariously low, particularly when the birds' Texas refuge supports some of the heaviest chemical barge traffic in the world.

A single toxic spill or natural disaster could wipe out the wild birds, which is why biologists raise captive flocks.

"Raising the chicks was a horrible experience," said Dr. Gee, remembering when the first birds were hatched in captivity. "We could hardly keep them alive."

The Patuxent flock began with one crippled bird from Woods Buffalo National Park, and the first chicks came from eggs laid by wild birds.

Disease, injury and predators have confounded the biologists' efforts, but perhaps the greatest challenge has been creating conditions that enable the birds to mate and breed in captivity.

"We developed all kinds of husbandry protocols," Dr. Gee said. "Then it took 20 years before we were effective at it."

Success came last year, when captive whooping cranes conceived naturally for the first time. Previously, eggs had been fertilized through artificial insemination.

Whooping cranes are monogamous and mate for life; one nesting pair will claim a territory of hundreds of acres.

Their mating ritual includes an elaborate dance in which the birds leap stiff-legged into the air with wings outstretched. The birds bow to each other, circle and hover. Actual mating demands a lot of room, as the male mounts the upright female and the cranes use their wings to balance.

Natural mating requires that the birds be given huge pens -- 50 by 100 feet and 10 feet high. The pens are covered with netting so that the birds can remain full-winged to dance and balance.

Another problem is some cranes' lack of ability as parents, infertility and the tendency of a mother to lay a single egg before smashing it with her bill. One-third of last year's eggs were destroyed by the birds.

The captive flock, 36 adults and 13 youngsters, was deemed strong enough for its caretakers to give up six of the young to the wild.

The Florida flock is just a beginning. Dr. Gee anticipates establishing a third wild flock after the turn of the century.

The 12 fledgling cranes to be released in Florida -- eager adolescents ready to test their wings -- will be closely watched and protected.

If all goes well, 20 more birds will be released in 1994, then 20 birds a year for the next 10 years.

Because whooping cranes consider the territory where they learn to fly their home -- and because migration in whoopers is learned and not innate -- biologists hope they will become a non-migratory population.

A nonmigratory flock may have a far better chance of survival than a migratory one, Dr. Gee said.

An earlier experimental migratory flock at Grays Lake, Idaho, ended in near disaster when sandhill cranes incubated and hatched whooping crane eggs, then reared the chicks.

As the whoopers tried to migrate with their foster parents, they crashed into power lines and other man-made obstacles.

"It was carnage," Dr. Gee said.

Baltimore Sun Articles
|
|
|
Please note the green-lined linked article text has been applied commercially without any involvement from our newsroom editors, reporters or any other editorial staff.