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Whooping Crane in its natural wetlands habitat. Cliff Nieuwenhuis |
The whooping crane, standing five feet tall with a seven-foot wingspan, is one of the world’s most majestic creatures. Affectionately called a "whooper," the whooping crane is named for its unusual call, which can be heard from up to two miles away.
Whooping crane chicks hatch covered in rusty brown down. The newborn’s blue eyes change to vivid aquamarine by the time the chick is three months old, then to bright gold three months later, and continue to deepen in color as the crane ages. As they mature, whoopers lose their early brown coloring and develop snow-white body feathers with jet-black wingtips visible only during flight. Their heads are red and black with a bare red "bald spot" on the forehead. Although one-year-old whoopers are considered adults, whooping cranes don’t mate until the age of four. In its natural wetlands habitat, the crane has a lifespan of about 25 years.
The crane’s distinctive call is generated by resonance in its five-foot-long trachea, half of which is coiled behind its breastbone. The call is used during the whooping crane’s dramatic courtship dance of calling, wing flapping, head bowing, jumping, bobbing, and weaving. This mating ritual actually affects the biological rhythms of the cranes, which mate for life, and helps prepare them for reproduction.
After mating, whooping cranes build a nest and the female lays two large eggs between late April through mid-May. Both parents incubate them for a month. The eggs hatch at different times and the second chick is usually pushed out of the nest or starved. Even though the chicks can swim as soon as they hatch and learn to fly in less than three months, they must also be taught how to eat and drink. The parents teach hunting techniques by demonstrating how to catch insects, small fish, invertebrates, and small mammals like mice. Adult cranes may scavenge dead ducks, marsh birds or muskrats.
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Cranes eating in a marsh.
FWS |
Although the whooping crane is among the world’s tallest and most beautiful birds, it is also one of the world’s most endangered. It is estimated that there were only 15, 000 cranes in North America when the first Europeans arrived and by the mid-1920s the number of cranes had shrunk to somewhere between 450 and 1,150.
The Aransas National Wildlife Refuge was established on the Texas Gulf coast over sixty years ago to protect the last migratory flock of this highly endangered species of crane, which in the early 1940s was down to 13 adults and 2 juveniles. Aransas National Wildlife Refuge is located on 59,000 acres of deep, sandy soils covered by grasslands, live oaks, and redbay thickets. Aransas provides habitat for pelicans, herons, egrets and a host of other birds, as well as for alligators, bobcats, and a variety of fish.
But the protected habitat at Aransas alone was not enough to restore the whooping crane population. Consequently, the National Wildlife Refuge System’s whooping crane program has grown and expanded. Patuxent National Wildlife Refuge in Maryland is part of a successful captive-breeding program, and Necedah National Wildlife Refuge in Wisconsin and Chassahowitzka National Wildlife Refuge in Florida are working to build a migratory flock of whoopers in the eastern United States.
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Whooping cranes learning to migrating by following an ultra-light aircraft. FWS |
Patuxent Research Refuge became the first captive-breeding site to close the reproductive loop when one of its whoopers laid eggs in 1975. There are now successful captive-breeding programs for whooping cranes at several sites. The Whooping Crane Eastern Partnership was created as a result of the Canadian and American International Whooping Crane Recovery Team’s urging that a migratory whooping crane population be established in the eastern United States. The members of the Partnership chose the Necedah National Wildlife Refuge and the Chassahowitzka National Wildlife Refuge as sites for the project because the refuges are within the historic range of the species yet far enough away from existing migratory flocks so as not to cause interference.
The team decided to use an ultralight aircraft and imprinting to teach the whooping cranes to migrate between Florida and Wisconsin. Human surrogate parents would remain silent, dressed head to toe in white fabric costumes and hold puppets in their hands in an effort to resemble a crane. Then ultralight aircraft would lead the crane migration.
The experiment was first performed on sandhill cranes, which are related to the whoopers but not endangered. The successful imprinting and migration of the sandhill cranes promised a similar success story for their whooping cousins. In 2001, the whooping cranes following the ultralight aircraft to Florida took 50 days and 26 stops to complete the 1,228-mile trip. After wintering at Chassahowitzka, the cranes began their northern migration on April ninth of 2002. Remarkably, the birds took a more direct route and made it back to Necedah in only 11 days. The cranes flew for an average of seven hours and covered more than 200 miles each day.
National wildlife refuges have provided habitat and protection, allowing for a ten-fold increase of the migratory flock of whooping cranes in recent years. The Whooping Crane Eastern Partnership has established a goal of having 125 birds in the new migratory flock by 2020, including at least 25 breeding pairs, as they work to reintroduce these magnificent birds to lands they had not populated for an entire century.
