Crane, Whooping


Grus americana


Adults are white with a red crown and a long, dark, pointed bill; juveniles are pale brown; in flight neck is held extended from the body while long legs trail behind and black flight feathers are visible; Ht – 5 feet (1.5 m), wingspan – 7.5 ft (2.3 m), Wt – males 16.5 lbs. (7.5 kg), females 14.3 lbs. (6.5 kg).

Family

Gruidae

Order

Gruiformes

Class

Aves

Range

Historical – from central Canada to Mexico, Utah eastward to the Atlantic Coast; currently – the only wild self-sustaining flock breeds in Wood Buffalo National Park, Northwest Territories, Canada, and winters in Aransas National Wildlife Refuge, Texas.

Habitat

Nests in the northern tallgrass prairie of the upper Midwest, the eastern aspen parklands of Canada, and the taiga and sub-Arctic regions of the Northwest Territories; winter habitats of varied wetland ecosystems are used from the high plateau wetlands of Mexico to the coastal wetlands along the Gulf and Atlantic Coasts of the southeastern U.S.

Life Expectancy

At least 30 years in the wild and up to 40 years in captivity have been documented.

Sexual Maturity

3 to 5 years.

Diet

In the wild, their summer diet consists of berries, crabs, fish, clams, snails, insects, snakes, frogs, smaller birds, acorns, and plant tubers, and in the winter it predominantly consists of animal food, especially blue crabs and clams, with smaller amounts of plant material, In the Zoo, they are fed a scientifically developed nutritionally balanced crane pellet, chopped greens, crickets, mealworms and vitamin and mineral supplements.

Status

IUCN - Endangered, CITES - Appendix I

Behaviors

Whooping crane pairs establish lifelong bonds that are reinforced and maintained through courtship “dances” and displays. Pairs make loud trumpeting calls during courtship and in flight. The female initiates the courtship calls and utters two higher-pitched calls for every lower-pitched call of the male. While calling, whooping cranes stand in an upright posture usually with their heads tilted back and beaks skyward. The male lifts his wings over his back during the unison call while the female keeps her wings folded at her sides. All cranes engage in “dancing”, which is characterized by behaviors such as bowing, jumping, running, stick or grass tossing and wing flapping. Most commonly these behaviors are associated with courtship; however, they may be seen in any season. In addition to strengthening the pair bond, these behaviors may also relieve tensions and stop aggression. Pairs construct large mounded nests of bulrush and other wetland vegetation on the ground in marshy areas. Females lay two large eggs approximately 2 to 3 days apart in May that both parents incubate. After 32 to 34 days, the eggs hatch and both parents feed the hatchlings. The older chick, however, has the advantage and typically the younger chick is either trampled or thrown out of the nest, leaving just one chick for the parents to rear. Chicks fledge (have matured enough to achieve flight) between 80 & 90 days. By 120 days, they are able to accompany their parents on the 2,100 mile migration south. Parents will feed their chicks until 8 or 9 months of age, and chicks will stay with their parents through their first year.

Adaptions

Crane eyes are designed for clear vision in daylight, from early morning light to high noon and then on into the evening, but the pupil isn’t big enough for night vision. Its skull is designed to slightly shade the eyes from overhead sun, and to allow the crane to see in front, to the side, partly above, and partly below. A baby crane’s head is covered with feathers. As the bird reaches maturity, the feathers on its crown fall out to reveal thick, bumpy red skin. Adults keep that bald crown for life. The color intensifies when the bird is mating or territorial. The crown enlarges or shrinks depending on whether the crane needs to draw attention to itself or is hiding. Cranes have excellent hearing, even though we cannot see their ears. The ears are protected by a layer of feathers. Their sense of smell may be no better than ours, but cranes have a perforated nostril like vultures and some other birds with good senses of smell. Cranes don’t have feathers protecting their nostrils the way woodpeckers must. Whooping cranes eat a lot of blue crabs, but it’s hard to be sure how well developed their sense of taste is. They have few tastebuds, and their tongue is pointed and shorter than their beak so they cannot bite it. The beak is pointed in front, but the mouth is wide enough at the gape (the “corners” of the mouth, where the upper and lower beak meet) to handle a big blue crab. The beak is not thick and strong enough to allow cranes to strike at fish as herons do, but does allow them to pick at a wide variety of food items from root tubers of plants to blue crabs, snakes, and mice. A whooping crane’s trachea is straight along the length of the neck, but coils dramatically as it reaches the body cavity, inside the sternum. Although we cannot see this on the outside, its huge trachea allows the crane to produce especially loud, resonating sounds in the way that a tuba can produce louder, more resonant sounds than those of a tiny trumpet. A whooping crane’s voice can carry over 5 miles—thanks to its long, coiled trachea. The esophagus is softer and stretchier than the trachea. It carries food from the mouth to the stomach, and can stretch enough for the crane to swallow large blue crabs. Under the neck feathers are a very thin layer of skin and a thicker layer of muscle that moves the neck around. A crane’s neck can reach down to the ground and water to feed, stretch up as high as the crane can reach for bugling and dancing, and turn all around to look about and to preen the body’s back and underside. The skin and muscles have to be stretchy, too. A crane’s neck needs to be as skinny as possible so that the crane can easily maneuver it all directions for feeding, preening, dancing, calling, and watching out for predators. Long, broad wings like a crane’s take too much energy to flap long distances. Like all birds, cranes must minimize the energy they need for flight over long distances. Birds with long, broad wings usually are long distance migrants, or they hunt by soaring for long periods each day (like vultures and some hawks). The pigment that makes a whooping crane’s wing feather tips black also makes those feathers stronger, which is important on their long-distance flights. The heart and lungs are so efficient that cranes can get enough oxygen to fly even at high altitudes. Cranes have a very short tail. Tails are useful for quick aerial maneuvers, but cranes fly slowly and directly, or spiral upwards on thermals in wide circles. That means a long tail wouldn’t be useful for them, and might actually drag in water, making it difficult to take off fast if a predator suddenly appeared. Long, skinny legs are useful for standing in water without getting body feathers wet, and also for balancing a long skinny neck when a bird is in flight. (There are exceptions: geese and swans have long necks and short legs, and Black-necked Stilts have very long legs and medium necks.) When baby cranes hatch, their legs are short. Babies hatch early enough in the season that plants are not very tall yet, but a baby crane’s legs must grow very fast to keep up with plant growth so they can see over the grass and leaves to follow their parents! Cranes nest on the ground, so their back toe can be very tiny, as for most other water birds. The toes are long enough to balance and support the crane’s body on soft mud.

Special Interests

The Family name Gruidae was derived from the Greek geranos, which refers to the guttural, rippling vocalizations of cranes. The name crane comes from an old Celtic word, garan, meaning “calling” or “crying out”. Large cranes have often been a source of meat for human populations worldwide. The rarer these birds became, the higher prices went for any part of the bird, including the eggs.

Folklore

The Eskimos of northwestern Alaska tell the following tale: One cold autumn day long ago, the cranes began to prepare to fly south. As they gathered in a huge flock, they saw a beautiful young girl. They coveted her loveliness and finally decided to take her with them. Surrounding her, they lifted her on widespread wings and carried her away. When she began to cry for help, they flew close together, drowning her small voice with their mighty cries. So today, when the cranes fly close together, sounding their loud trumpet calls, it is time for all Eskimo children to come inside and stay close to their family. Another ancient belief about migrating cranes is that they swallowed a stone for ballast before departing on their journey. This would help keep them on course even in high winds. Source: The Folklore of Birds, by Laura C. Martin © 1993, The Globe Pequot Press, Old Saybrook, CT

Conservation

Before the first Europeans arrived in North America, biologists estimate that the whooping crane population numbered 10,000. By the 1870’s, that number had been reduced to 1,300 – 1,400. In 1944, only 21 whooping cranes could be found. Habitat destruction, hunting and displacement activities of man caused their near extinction. Today, degradation of coastal wetlands, elimination and destruction of stop over wetlands during migration and increased construction of power lines threaten their continued survival. Today, through intensive conservation efforts, there are 373 cranes in the wild and another 145 in captivity (statistics from the Whooping Crane Conservation Association website 12/18/2006). Florida’s Fish and Wildlife Conservation Commission (FWC) has joined forces with 19 other agencies in the Whooping Crane Eastern Partnership to help restore the whooping crane to their former southeastern United States range. One project is reintroducing a migratory flock. Every fall since 2001, captive hatched juveniles are led by a whooping crane decorated and human piloted ultralight on a 1,200 mile migration. In October, chicks leave their breeding grounds in Necedah National Wildlife Refuge, Wisconsin, and fly to their wintering grounds in Chassahowitzka National Wildlife Refuge along Florida’s Gulf Coast. Once they learn the migration route south, they are able to return north without human assistance. The greatest threats to their survival during this annual migration are collisions with power lines, loss of habitat and predator attacks. To learn how you can help or to follow the whooping cranes on their ultralight led migration (October – December) visit the Whooping Crane Eastern Partnership website at http://www.bringbackthecranes.org.

Jacksonville Zoo History

The first pair of whooping cranes to be exhibited at the Jacksonville Zoo and Gardens went on display in February 2007. Due to slight leg abnormalities, these captive hatched juveniles were not able to be released into the wild as part of the Whooping Crane reintroduction program and are here through a permit of the USFWS.

Exhibit

Wild Florida