Text by Eileen Dowd Stukel
Photo by Doug Backlund
 

"Think global, act local." This environmental slogan could well be the theme song for the whooping crane (Grus americana). Once reduced nearly to extinction, the whooping crane survives today only because of an international commitment to this majestic species, the tallest bird in North America.

The whooping crane’s story shares common threads with the sagas of other rare species. No good estimate of its historical population exists. But by the mid-1800s, biologists estimate that only 1300 to 1400 individuals remained. During this time, nesting areas stretched from northern Illinois northwestward through parts of Iowa, Minnesota, North Dakota, Manitoba, Saskatchewan, and Alberta.

Continuing on its downward spiral, by the mid-1930s the species was reduced to just two populations. A nonmigratory flock lived in southwestern Louisiana and a migratory population wintered along Texas’ Gulf Coast and nested in parts unknown. Most of the Louisiana birds were lost in a hurricane in 1940, leaving the migratory flock as the species’ only hope of survival. A major breakthrough came in 1954, when the only known nesting area remaining in the world was discovered in Wood Buffalo National Park, Northwest Territories, Canada.

Another characteristic of many rare species tales is that often many factors contributed to a species’ precarious decline. Wetland drainage, conversion of native habitats for cultivation and settlement, shooting for meat and curiosity, and disturbance of these extremely sensitive birds likely played roles that resulted in a count of only 18 whoopers on its Texas wintering grounds in 1938-39.

A third common thread often tying endangered species together is the tremendous investment of time, energy and funds necessary for the slow journey back to recovery. While frustrating to many, to others such an investment represents a lesson that we should strive to "keep common species common", a theme of the current Teaming with Wildlife campaign to secure stable funding for fish and wildlife species.

Whooping cranes mate for life, and individuals may live in the wild for 22 to 24 years. Birds typically mature at three to four years of age, with most females producing eggs by their fourth year. The pair selects a nest site within the spruce bog habitat of Wood Buffalo. The area near its nest has abundant food, such as aquatic insects, mollusks and crustaceans. The female typically lays two eggs sometime between late April and mid May. Since the iceless season in this area lasts for only four months, the pair has little time to renest unless the pair loses its first nest very early in the season.

The chicks don’t hatch at the same time. By the time the second egg hatches, the older chick is usually stronger than the younger chick, which often doesn’t survive. Scientists have put these potentially "wasted" eggs to use by taking one of the eggs from the nest to hatch it in captivity. The pair tolerates this single, brief disturbance. These second eggs have allowed the establishment of three captive populations of whooping cranes, which are used for research and reintroduction projects.

Both parents share incubation duties, which last for 29 to 31 days. The female often assumes nighttime incubation duty and is the primary caregiver in feeding and caring for young. For the first three weeks of life, the chicks and their parents stay near the nest, with parents brooding young at night and during bad weather. Parents introduce the chicks to their omnivorous diet. Summer foods may include insects, frogs, small birds, rodents, minnows, and berries.

Family groups begin migrating in mid-September, traveling 2500 miles to Aransas National Wildlife Refuge in Texas. Unlike sandhill cranes, which migrate in large flocks, whoopers typically travel as a pair, a family group, or in a very small flock. Nearly all the birds in this main migratory flock travel through South Dakota, stopping when necessary to feed and rest. Not surprisingly, migrating whoopers select quiet, isolated areas for stops, often feeding in agricultural fields with waste grain and roosting in shallow wetlands or on sandbars within river channels. Whoopers migrate during the day, although foul weather or unfavorable winds may stall them. Although documented in such counties as Pennington, Kingsbury, and Beadle, most migrating whooping cranes confine themselves to the central third of South Dakota.

Whoopers stay on their wintering grounds for nearly six months, remaining as family groups with distinct territories. Winter foods include blue crabs, clams, and wolfberry, although they may take advantage of supplies of other foods, such as acorns, snails, and insects. By mid-March, adults start dancing and calling, signs of restlessness to begin their northward migration. Family groups typically leave together between late March and mid-April. Although the previous year’s young separate from their parents during migration or soon after arriving at Wood Buffalo, they usually spend their second summer close to their natal site.

The single migratory flock of whoopers is extremely vulnerable to a natural or human-caused catastrophe, such as a severe storm or hurricane or an oil spill in the Gulf Intracoastal Waterway, located near the wintering grounds. Because of this vulnerability, researchers have tried several experiments to enhance the species survival odds. In a long-term experiment to establish a second migratory flock, whoopers were cross-fostered to sandhill cranes, meaning that sandhill adults reared whooper chicks. The experiment ended when researchers concluded that the whoopers would not mate with other whoopers, presumably because they were reared by sandhills. A current experiment is underway to establish a nonmigratory flock in Florida. A second effort is to train whoopers to migrate between Idaho and New Mexico by having them follow an ultra-light aircraft, as if following their parents in migration.

By the time you read this article, whoopers will be making their way back to Wood Buffalo for another breeding season. According to U.S. Fish and Wildlife Service estimates, 182 whoopers are expected to be part of the 1998 spring migration. If you’re lucky enough to view migrating whooping cranes, be extremely cautious about disturbing them. View them from a distance with binoculars or a spotting scope, and don’t approach the birds. Report the sighting and any observation of colored leg bands to the Game, Fish and Parks Department and the U.S. Fish and Wildlife Service. Consider yourself privileged to view this elegant bird and give it the space and solitude it needs.

I just saw some whooping cranes! Or did I? Here are some clues to help distinguish whooper lookalikes.

sandhill crane:
gray with dark wingtips
5-foot wingspan
travels in large flocks

snow goose:
white with black wingtips
3- to 4-foot wingspan
rapid wingbeat
short legs don’t extend beyond tail in flight

swan:
all white
long extended neck
6-foot wingspan
short legs don’t extend beyond tail in flight

white pelican:
white with black wing edging
long neck, folded in flight
8-foot wingspan
short legs don’t extend beyond tail in flight
travels in flocks of 20 or more

egret:
all white or mostly white
long neck, folded in flight
slow wingbeat
long legs extend beyond tail in flight

whooping crane:
white with black wingtips
neck and legs extended in flight
7-foot wingspan
travels in group of 2 to 7 birds