North Florida Ecological Services Office
Southeast Region

Species Status and Fact Sheet


WHOOPING CRANE

Grus americana

FAMILY: Gruidae

STATUS:
Endangered, Federal Register (FR), March 11, 1967
Florida Experimental Population, FR, January 22, 1993
Rocky Mountain Experimental Population, FR, July 21, 1997
Eastern Migratory Experimental Population, FR, March 9, 2001

DESCRIPTION: The whooping crane is the tallest North American bird. Males, which may approach 1.5 meters in height, are larger than females. Adults are snowy white except for black primary feathers on the wings and a bare red face and crown. The bill is a dark olive-gray, which becomes lighter during the breeding season. The eyes are yellow and the legs and feet are gray-black. Immature cranes are a reddish cinnamon color that results in a mottled appearance as the white feather bases extend. The juvenile plumage is gradually replaced through the winter months and becomes predominantly white by the following spring as the dark red crown and face appear. Yearlings achieve the typical adult appearance by late in their second summer or fall. The life span is estimated to be 22 to 24 years in the wild. Whooping cranes are omnivorous feeders. They feed on insects, frogs, rodents, small birds, minnows, and berries in the summer. In the winter, they focus on predominantly animal foods, especially blue crabs and clams. They also, forage for acorns, snails, crayfish and insects in upland areas.

REPRODUCTION AND DEVELOPMENT: Whooping cranes are monogamous and form life-long pair bonds but will remate following the death of a mate. Whooping cranes return to the same breeding territory in Wood Buffalo National Park, Canada, in April and nest in the same general area each year. They construct nests of bulrush and lay one to three eggs, (usually two) in late April and early May. The incubation period is about 29 to 31 days. Whooping cranes will renest if the first clutch is lost or destroyed before mid-incubation. Both sexes share incubation and brood-rearing duties. Despite the fact that most pairs lay two eggs, seldom does more than one chick reach fledging. Autumn migration begins in mid-September, and most birds arrive on the wintering grounds of Aransas National Wildlife Refuge on the Texas Gulf Coast by late-October to mid-November. Whooping cranes migrate singly, in pairs, in family groups or in small flocks, and are sometimes accompanied by sandhill cranes. They are diurnal migrants, stopping regularly to rest and feed, and use traditional migration staging areas. On the wintering grounds, pairs and family groups occupy and defend territories. Subadults and unpaired adult whooping cranes form separate flocks that use the same habitat but remain outside occupied territories. Subadults tend to winter in the area where they were raised their first year, and paired cranes often locate their first winter territories near their parents' winter territory. Spring migration is preceded by dancing, unison calling, and frequent flying. Family groups and pairs are the first to leave the refuge in late-March to mid-April.

Juveniles and subadults return to summer in the vicinity of their natal area, but are chased away by the adults during migration or shortly after arrival on the breeding grounds. Only one out of four hatched chicks survive to reach the wintering grounds. Whooping cranes generally do not produce fertile eggs until age 4.

RANGE AND POPULATION LEVEL:

Historic: The historic range of the whooping crane once extended from the Arctic coast south to central Mexico, and from Utah east to New Jersey, into South Carolina, Georgia, and Florida. The historic breeding range once extended across the north-central United States and in the Canadian provinces, Manitoba, Saskatchewan, and Alberta. A separate non-migratory breeding population occurred in southwestern Louisiana.

Aransas/Wood Buffalo Population: The current nesting range of the self-sustaining natural wild population is restricted to Wood Buffalo National Park in Saskatchewan, Canada and the current wintering grounds of this population are restricted to the Texas Gulf Coast at Aransas National Wildlife Refuge and vicinity. is experiencing a gradual positive population trend overall, although some years exhibit stationary or negative results. In January, 2000, there were 187 individuals in the flock, including 51 nesting pairs.

Rocky Mountain Experiment: In 1975, an effort to establish a second, self-sustaining migratory flock was initiated by transferring wild whooping crane eggs from Wood Buffalo National Park to the nests of greater sandhill cranes at Grays Lake National Wildlife Refuge in Idaho. This Rocky Mountain population peaked at only 33 birds in 1985. The experiment terminated in 1989 because the birds were not pairing and the mortality rate was too high to establish a self-sustaining population. In 1997, the remaining birds in the population were designated as experimental, non-essential to allow for greater management flexibility and to begin pilot studies on developing future reintroduction methods. In 2001, there were only two remaining whooping cranes in this population.

Captive Populations: As of March, 2001, there were 120 captive whooping cranes held at six facilities. Four facilities: Patuxent Wildlife Research Center, International Crane Foundation, Calgary Zoo, and San Antonio Zoo have successful breeding programs. Currently, the remaining facilities, Lowry Park Zoo and Audubon Institute house cranes for rehabilitative and educational purposes. Chicks produced at the captive facility either remain in captivity to maintain the health and genetic diversity of the captive flock, or are reared for release to the wild in the experimental reintroduction programs.

Florida Experimental Nonessential Population: An experimental reintroduction of whooping cranes in Florida was initiated in 1993 to establish a non-migratory population at Kissimmee Prairie. A nonmigratory population avoids the hazards of migration, and by inhabiting a more geographically limited area than migratory cranes, individuals can more easily find compatible mates. Since 1993, 233 isolation-reared whooping cranes have been released in the area. In Spring 2000, there were 65 individuals in the project area with 10 pairs defending territories and evidence of the first successful hatching of chicks. Annual releases of chicks are expected to continue to augment this new experimental population.

Eastern Migratory Population: A second experimental non-essential population is currently being reintroduced to eastern North America. The intent is to establish a migratory flock which would summer and breed in central Wisconsin, migrate across the seven states and winter in west-central Florida. The birds are taught the migration route after being conditioned to follow costumed pilots in ultralight aircraft. Initial experiments using sandhill cranes, completed in the Fall of 2000, successfully led 11 cranes 1,250 miles from Necedah National Wildlife Refuge in Wisconsin to Chassahowitzka National Wildlife Refuge in Florida. The birds winter in Florida and then migrate back to Wisconsin on their own in the Spring.

Following this success, the first attempt to lead whooping cranes was made in 2001. Seven birds made it to Florida and the five that survived the winter returned to central Wisconsin the following spring. An additional 16 birds were successfully reintroduced to the flyway in 2002. To date, 20 of the original 24 whooping cranes reintroduced have survived and adapted to the wild. Updated information on this project is available online at http://www.bringbackthecranes.org

HABITAT: The nesting area in Wood Buffalo National Park is a poorly drained region interspersed with numerous potholes. Bulrush is the dominant emergent in the potholes used for nesting. On the wintering grounds at Aransas National Wildlife Refuge in Texas, whooping cranes use the salt marshes that are dominated by salt grass, saltwort, smooth cordgrass, glasswort, and sea ox-eye. They also forage in the interior portions of the refuge, which are gently rolling, sandy, and are characterized by oak brush, grassland, swales, and ponds. Typical plants include live oak, redbay, Bermuda grass, and bluestem. The non-migratory, Florida release site at Kissimmee Prairie includes flat, open palmetto prairie interspersed with shallow wetlands and lakes. The primary release site has shallow wetlands characterized by pickerel weed, nupher, and maiden cane. Other habitats include dry prairie and flatwoods with saw palmetto, various grasses, scattered slash pine, and scattered strands of cypress. Areas selected for the proposed eastern migratory experimental population closely mimic habitat of the naturally occurring wild population in Canada and Texas.

REASONS FOR CURRENT STATUS: The whooping crane population, estimated at 500 to 700 individuals in 1870 declined to only 16 individuals in the migratory population by 1941 as a consequence of hunting and specimen collection, human disturbance, and conversion of the primary nesting habitat to hay, pastureland, and grain production. The main threat to whooping cranes in the wild is the potential of a hurricane or contaminant spill destroying their wintering habitat on the Texas coast. Collisions with power lines and fences are known hazards to wild whooping cranes. The primary threats to captive birds are disease and parasites. Bobcat predation has been the main cause of mortality in the Florida experimental population.

MANAGEMENT AND PROTECTION: The self-sustaining wild population is protected on public lands in the nesting area at Wood Buffalo National Park in Canada and on the principal wintering area at Aransas National Wildlife Refuge in Texas. A major traditional migratory stopover is at Salt Plains National Wildlife Refuge in Oklahoma. This population is closely monitored throughout the nesting season, on the wintering grounds, and during migration. The Canadian Wildlife Service and the U.S. Fish and Wildlife Service are involved in recovery efforts under a 1990 Memorandum of Understanding (MOU), "Conservation of the Whooping Crane Related to Coordinated Management Activities." All cranes within the Rocky Mountain, Florida non-migratory and proposed eastern migratory non-essential, experimental population areas are fully protected as a threatened species (instead of endangered), but other provisions of the Endangered Species Act are relaxed to allow for greater management flexibility as well as positive public support

REFERENCES:

  • U.S. Fish and Wildlife Service. 1986. Whooping Crane Recovery Plan. U.S. Fish and Wildlife Service, Albuquerque, New Mexico. vi + 283 pp.
  • U.S. Fish and Wildlife Service. 1993. Endangered and threatened wildlife and plants; Establishment of an experimental nonessential population of whooping cranes in Florida. Federal Register 58:5647- 5658.
  • U.S. Fish and Wildlife Service. 1997. Endangered and threatened wildlife and plants; Final Rule to Designate the Whooping Cranes of the Rocky Mountains as Experimental Nonessential and to Remove Whooping Crane Critical Habitat Designations from Four Locations. Federal Register 62:38932-44227
  • U.S. Fish and Wildlife Service. 2001. Endangered and threatened wildlife and plants; Proposal to Establish a Nonessential Experimental Population of Whooping Cranes in the Eastern United States. Federal Register 66:14107-14119.
  • For more information please contact:

    Mr. Tom Stehn
    Whooping Crane Coordinator
    Aransas National Wildlife Refuge
    P.O. Box 100
    Austwell, TX 77950
    (361) 286-3559
    Email: tom_stehn@fws.gov

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    Last updated: September 12, 2014