| Whooping Crane | |
|---|---|
| Conservation status | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Gruiformes |
| Family: | Gruidae |
| Genus: | Grus |
| Species: | G. americana |
| Binomial name | |
| Grus americana (Linnaeus, 1758) |
|
| Distribution map of the Whooping Crane (1995). blue: breeding, grey: summering, green: year-round, orange: wintering | |
The whooping crane (Grus americana), the tallest North American bird, is an endangered crane species named for its whooping sound. Along with the Sandhill Crane, it is one of only two crane species found in North America. The whooping crane's lifespan is estimated to be 22 to 24 years in the wild. There is an estimate of only 400+ left in the wild and 165+ in captivity.[2]
Contents |
Adult whooping cranes are white with a red crown and a long, dark, pointed bill. Immature whooping cranes are cinnamon brown. While in flight, their long necks are kept straight and their long dark legs trail behind. Adult whooping cranes' black wing tips are visible during flight.
The species can stand over 1.5 meters (5 feet) and have a wingspan of 2.3 meters (7.5 feet). Males weigh on average 7.0 kg (17 lb), while females weigh about 6.0 kg (14 lb).[3] The body length averages about 132 cm (52 in).[4] The only other very large, long-legged white birds in North America are: the Great Egret, which is over a foot shorter and one-seventh the weight of this crane; the Great White Heron, which is a morph of the Great Blue Heron in Florida; and the Wood Stork. All three other birds are at least 30% smaller than the whooping crane. Herons and storks are also quite different in structure from the crane.[5]
The muskeg of the taiga in Wood Buffalo National Park, Alberta, Canada, and the surrounding area was the last remnant of the former nesting habitat of the Whooping Crane Summer Range. However, with the recent Whooping Crane Eastern Partnership Reintroduction Project, whooping cranes nested naturally for the first time in 100 years in the Necedah National Wildlife Refuge in Central Wisconsin, USA. They nest on the ground, usually on a raised area in a marsh. The female lays 1 or 2 eggs, usually in late-April to mid-May. The blotchy, olive-colored eggs average 2½ inches in breadth and 4 inches in length (60 by 100 mm), and weigh about 6.7 oz (190 g). The incubation period is 29–31 days. Both parents brood the young, although the female is more likely to directly tend to the young. Usually no more than one young bird survives in a season. The parents often feed the young for 6–8 months after birth and the terminus of the offspring-parent relationship occurs after about 1 year.
Breeding populations winter along the Gulf coast of Texas, USA, near Corpus Christi on the Aransas National Wildlife Refuge and along Sunset Lake in Portland, Matagorda Island, Isla San Jose, and portions of the Lamar Peninsula and Welder Point, which is on the east side of San Antonio Bay.[6]
The Salt Plains National Wildlife Refuge in Oklahoma is a major migratory stopover for the crane population hosting over 75% of the species annually.[7][8]
The whooping crane is endangered mainly as a result of habitat loss, although whoopers are also still illegally shot despite this being subject to substantial financial penalties and possible prison time.[9][10][11]
At one time, the range for these birds extended throughout midwestern North America. In 1941, the wild population consisted of 21 birds. Conservation efforts have led to a population increase; as of April 2007 there were about 340 whooping cranes living in the wild, and another 145 living in captivity. The whooping crane is still one of the rarest birds in North America. The United States Fish and Wildlife Service confirmed that 266 whooping cranes made the migration to Aransas National Wildlife Refuge in 2007.[12]
Among the many potential nest and brood predators include American Black Bear (Ursus americanus), Wolverine (Gulo gulo), Gray Wolf (Canis lupus), Red Fox (Vulpes vulpes), Lynx (Lynx canadensis), Bald Eagle (Haliaeetus leucocephalus), and Common Raven (Corvus corax). Golden eagles have killed young whooping cranes and fledgings.[13] The bobcat has killed many whooping cranes in Florida and Texas; whether the birds were taken on their nests or not is not specified.[5] In Florida, bobcats have caused the great majority of mortalities among whooping cranes, including several adults and the first chick documented to be born in the wild in 60 years.[14][15][16][17][18][19] Patuxent Wildlife Research Center scientists believe that this is due to an overpopulation of bobcats caused by the absence or decrease in larger predators (the endangered Florida panther and the extirpated red wolf) that formerly preyed on bobcats.[15] At least 12 bobcats have been trapped and relocated in an attempt to save the cranes.[20] American alligators have taken a few whooping cranes in Florida.[15]
During the past two years, five whooping cranes in the Eastern population, which numbers about 100 in total, have been illegally shot and killed. One of the dead cranes was the female ("First Mom") who was the first captive raised and released whooper to successfully raise, along with her mate, a chick to adulthood in the wild in the East, in 2006. This was a particular blow to that population because whoopers in the East do not yet have an established successful breeding situation. Various agencies and individuals have offered rewards for the apprehension of the persons responsible. [9][10][11]
Although the individuals responsible for the deaths of four of the cranes have not yet been apprehended, on March 30, 2011, Wade Bennett, 18, of Cayuga, Indiana and an unnamed juvenile pled guilty to killing First Mom. After killing the crane, the juvenile had posed holding up its body. Bennett and the juvenile were sentenced to a $1 fine, probation, and court fees of about $500, a penalty which was denounced by various conservation organizations as being too light. The prosecuting attorney has estimated that the cost of raising and introducing to the wild one whooping crane could be as much as $100,000.[21][22][23][24]
In October 2011, two juveniles were apprehended for shooting to death two whooping cranes in Jefferson Davis parish in Louisiana.[25] The sandhill Cranes are the foster parents to the Whooping Cranes.
These birds forage while walking in shallow water or in fields, sometimes probing with their bills. They are omnivorous and slightly more inclined to animal material than most other cranes. In their Texas wintering grounds, this species feeds on various crustaceans, mollusks, fish (such as eel), berries, small reptiles and aquatic plants. Potential foods of breeding birds in summer include frogs, small rodents, smaller birds, fish, aquatic insects, crayfish, clams, snails, aquatic tubers and, berries. Waste grain, including wheat, barley, and corn, is an important food for migrating whooping cranes.[5]
The whooping crane was declared endangered in 1967. Attempts have been made to establish other breeding populations in captivity.
Subsequent to hatching, the Operation Migration cranes are taught to follow their ultralight aircraft, fledged over their future breeding territory in Wisconsin, and led by ultralight on their first migration from Wisconsin to Florida; the birds learn the migratory route and then return, on their own, the following spring. This reintroduction began in fall 2001 and has added birds to the population in each subsequent year (Except that in early 2007, a disastrous storm killed all of the 2006 yearlings after their arrival in Florida.).
As of September, 2007, there were 52 surviving whooping cranes in the Eastern Migratory Population (EMP), including 2 of the 4 yearlings released in Wisconsin and allowed to migrate on their own (Direct Autumn Release (DAR)). Fourteen of these birds had formed seven pairs; two of the pairs nested and produced eggs in spring 2005. The eggs were lost due to parental inexperience. In spring 2006 some of the same pairs have again nested and are incubating eggs. Two whooping crane chicks were hatched from one nest, on June 22, 2006. Their parents are both birds that were hatched and led by ultralight on their first migration in 2002. At just 4 years old these are young parents. The chicks are the first whooping cranes hatched in the wild, of migrating parents, east of the Mississippi, in over 100 years. One of these young chicks was unfortunately predated on the Necedah National Wildlife Refuge. The other young chick, a female, has successfully migrated with her parents to Florida. As noted above, in early February, 2007, 17 yearlings in a group of 18 were killed by the 2007 Central Florida tornadoes. All birds in that flock were believed to have died in the storms, but then a signal from one of the transmitters, "Number 15-06", indicated that it had survived. The bird was subsequently relocated in the company of some Sandhill Cranes. It died in late April from an as yet unknown cause, possibly related to the storm trauma. Two of the 4 DAR Whooper chicks from 2006 were also lost due to predation.[34][35] However, as of December, 2010, 105 birds had become established in the eastern United States population.[36]
In Wood Buffalo National Park, the Canadian Wildlife Service counted 73 mating pairs in 2007. They produced 80 chicks, of which 40 survived to the fall migration, and 39 completed the migration to Aransas National Wildlife Refuge.[12]
|
||||||||||||||||||||||||||