Crane Chick May Be First Hybrid in Wild

Biologists for years have tried to play Cupid to a small crowd of whooping cranes living among a huge flock of their distant cousins, sandhill cranes.

These efforts to boost the numbers of the whooping crane, prominent on the federal endangered species list, began with the hand-placement of whooper eggs in the sandhills’ nests. Now the hope of fostering family life among the whoopers may have finally yielded results--sort of.

What appears to be a hybrid whooping-sandhill crane turned up Nov. 5 at Bosque del Apache National Wildlife Refuge, 85 miles south of Albuquerque in the Rio Grande Valley in south-central New Mexico.

If the chick is confirmed as a hybrid, it would be the first known instance of sandhills and whoopers crossing in the wild, U.S. Fish and Wildlife Service officials said.

The young bird, born in June and already nearly full height, looks like a juvenile whooper: whitish with a pale reddish-brown head and neck, with scattered reddish-brown feathers over the rest of its body.

But its bill is a bit shorter and its wingtips appear gray instead of black, said Phil Norton, refuge manager and a wildlife biologist.

“I don’t know what else it could be,” he said. “There’s absolutely nothing else that it could be.”

Researchers don’t want a hybrid diluting the sandhill or whooper gene pools, said George Gee, head of captive propagation research at the endangered species research branch at the Patuxent Wildlife Research Center at Laurel, Md.

But Norton said there is no rush to remove the suspected hybrid from the wild because it is probably infertile, judging from past experience with whooper-sandhill crosses. Its ability to reproduce will not be known until it reaches breeding age in four or five years.

And the gender and genetic heritage of the new bird will not be known until early next year, when it molts and loses its baby feathers.

The new bird’s father is most likely a whooper that likes to spend its winters alone in a field at Lemitar, about 20 miles north of the Bosque del Apache, Norton said.

The male has been hanging around a female sandhill crane and the juvenile at Bosque del Apache.

“Everybody knew it was biologically possible, but everybody felt like it wouldn’t happen because of different mating habits and rituals,” Norton said. “Who knows? Maybe after eight years of abstinence, it kind of makes you want to do your own thing.”

Whooping cranes, native to North America and named for their loud whooping honk, are white with black-tipped wings. America’s tallest bird, in adulthood they reach about five feet and have wingspans of 7 1/2 feet.

The flourishing sandhill crane mainly inhabits east and central North America and is bluish-gray tinged with a sandy yellow.

The suspected hybrid belongs to a flock of about 20,000 sandhills and about 10 whoopers that spend summers at Grays Lake National Wildlife Refuge in southeastern Idaho. The group migrates 750 miles each year to its southern wintering grounds along the Rio Grande Valley.

Scientists believe the whooping crane never existed in great numbers, probably peaking in the late 19th Century at 500 to 1,200 birds. The bird approached extinction by the middle of this century, as humans turned the birds’ habitats into farms and cities and hunters nearly finished them off.

The number of known whooping cranes dwindled to 16 in 1941, and after World War II scientists began trying to encourage them to breed. The federal government listed whoopers for protection as an endangered species in 1967.

Since then, the whooper population has increased to around 240 in two wild flocks and in captivity.

A flock of about 140 whooping cranes migrates in winter to the Arkansas National Wildlife Refuge on the Texas Gulf Coast. In summer, they nest 2,500 miles to the north at Wood Buffalo National Park in Canada’s Northwest Territory.

In addition, the International Crane Foundation at Baraboo, Wis., has 37 whoopers. Fifty-two whoopers live at the Patuxent center, and there are two at the San Antonio Zoo.

Gee said four whooper-sandhill hybrids--two males and two females--were produced at Patuxent about 1975. “Our experience has shown them to be sterile,” he said.

The females produced no eggs, despite two years of efforts to mate them. Then the females and one male fell prey to foxes.

The surviving male has been repeatedly mated with other females--sandhills and whoopers--but yielded no young, Gee said. The males’ sperm cells were misshapen and less numerous than expected, he said.

Hybrids, which lack the whooper’s black mustache, and have whitish to light dusty-gray plumage, were raised “because we were concerned what might happen in the wild in Idaho where (whoopers) were reared under sandhill cranes in the wild,” Gee said. The objective was to discover what would happen if the birds mated in the wild.

The 10 whoopers in the Grays Lake group are all that remain of an experimental flock established in 1975 when biologists placed whooper eggs in the sandhill cranes’ nests. Researchers hoped to inspire a second whooper flock in case a natural disaster or disease decimated the Aransas flock.

Though the number of sandhill-raised whoopers at Grays Lake reached 33 in the winter of 1984-85, they failed to bond in male-female pairs, and that approach was abandoned in 1988.