The whooping crane (Grus americana) is an endangered crane species, native to North America, named for its "whooping" calls. Along with the sandhill crane (Antigone canadensis), it is one of only two crane species native to North America, and it is also the tallest North American bird species, with an estimated 22–30+ year life expectancy in the wild. After being pushed to the brink of extinction by unregulated hunting and loss of habitat that left just 21 wild (and two captive) cranes by 1941, the whooping crane made a partial recovery through conservation efforts. The total number of cranes in the surviving migratory population, plus three reintroduced flocks and in-captivity, is just over 830 birds . This includes about 560 individuals in the remnant population that migrates between coastal Texas, USA, and the Northwest Territories, Canada, which is termed the "Aransas-Wood Buffalo Population" after the protected areas that anchor the population's wintering and breeding ranges, respectively. Additionally, there are about 140 individuals in two reintroduced populations breeding in Wisconsin and Louisiana, USA, and an additional 130 individuals in captivity.
Taxonomy The whooping crane was formally described in 1758 by the Swedish naturalist Carl Linnaeus in the tenth edition of his Systema Naturae. He placed it with the herons and cranes in the genus Ardea and coined the binomial name Ardea america. Linnaeus based his description on the accounts of two English naturalists. In 1729–1732 Mark Catesby had described and illustrated the whooping crane in his The Natural History of Carolina, Florida and the Bahama Islands, and in 1750 George Edwards had described and illustrated the crane using a preserved specimen that had been brought to London from the Hudson Bay area of northeast Canada by James Isham, an employee of the Hudson's Bay Company. Linnaeus specified the type locality as North America but this has been restricted to the Hudson Bay. The whooping crane is now one of eight species placed in the genus Grus that was introduced in 1760 by the French zoologist Mathurin Jacques Brisson. There are no recognised subspecies.
Distribution and habitat
At one time, the range for the whooping crane extended throughout midwestern North America as well as southward to Mexico.Putnam, Michael & Partida, Ruth & Gomez, Suix & Lacy, Anne. (2008). The Whooping Crane in Mexico: Past, Present, and Future?.. Downloaded on 04 March 2021 By the mid-20th century, the muskeg of the taiga in Wood Buffalo National Park, Alberta and Northwest Territories, Canada, and the surrounding area had become 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, United States, and these have subsequently expanded their summer range in Wisconsin and surrounding states, while reintroduced experimental non-migratory populations have nested in Florida and Louisiana. However, the reintroduction in Florida has been halted and is considered a failure as a result of high adult mortality, low juvenile recruitment, and high rates of habitat loss
Whooping cranes 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-coloured eggs average 2½ inches in breadth and 4 inches in length (60 by 100 mm), and weigh about . 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, United States, near Rockport 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.
The Salt Plains National Wildlife Refuge in Oklahoma is a major migratory stopover for the crane population, hosting 60-75% of the species annually.
As many as nine whooping cranes were observed at various times on Granger Lake in Central Texas in the 2011/2012 winter season. Drought conditions in 2011 exposed much of the lake bed, creating ample feeding grounds for these cranes just as they were taking their autumn migration through Texas.
Description
An adult whooping crane is white with a red crown and a long, dark, pointed bill. However, 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.
Size
On average, the whooping crane is the fifth-largest extant species of crane in the world.Johnsgard, P. A. (1983). Cranes of the World. Indiana University Press. Whooping cranes are the tallest bird native to North America and are anywhere from the third to the fifth heaviest species on the continent, depending on which figures are used. The species can reportedly stand anywhere from in height.Collar, J., Del Hoyo, J., Elliot, A., & Saragatal, J. (1996). Handbook of the birds of the World. Volume 3. Hoatzin to auks. Lynx Edicions.Soothill, E., & Soothill, R. (1982). Wading birds of the world. Blandford Press. Wingspan, at least typically, is from . Widely reported averages put males at a mean mass of , while females weigh on average (Erickson, 1976). However, one small sample of unsexed whooping cranes weighed on average. Typical weights of adults seem to be between . The body length, from the tip of the bill to the end of the tail, averages about . The standard linear measurements of the whooping cranes are a wing chord length of , an exposed culmen length of and a tarsus of .Fisher, H. I., & Goodman, D. C. (1955). The myology of the whooping crane, Grus americana. Illinois biological monographs; v. 24, no. 2.
The only other very large, long-legged white birds in North America are: the great egret, which is over a foot (30 cm) 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. Larger individuals (especially males of the larger races) of sandhill crane can overlap in size with adult whooping cranes but are obviously distinct at once for their gray rather than white color.Johnsgard, P. A. (2015). A chorus of cranes: the cranes of North America and the world. University Press of Colorado.
Vocalizations Their calls are loud and can carry several kilometers. They express "guard calls", apparently to warn their partner about any potential danger. A crane pair jointly calls rhythmically ("unison call") after waking in the early morning, after courtship, and when defending their territory. The first unison call ever recorded in the wild was taken in the whooping cranes' wintering area of the Aransas National Wildlife Refuge during December 1999.
Predators
Their many potential nest and brood predators include the American black bear, wolverine, gray wolf, cougar, red fox, Canada lynx, bald eagle, and common raven. Golden eagles have killed some young whooping cranes and fledglings. Due to their large size, adult birds in the wild have few predators.Red River Chloride Control Project, Supplement I to the FEIS: Environmental Impact Statement, United States. Army. Corps of Engineers,1995 However, American alligators have taken a few whooping cranes in Florida, and the bobcat has killed many captive-raised whooping cranes in Florida and Texas. In Florida, bobcats have caused the great majority of natural mortalities among whooping cranes, including several ambushed adults and the first chick documented to be born in the wild in 60 years. Adult cranes can usually deter or avoid attacks by medium-sized predators such as coyotes when aware of a predator's presence, but the captive-raised cranes haven't learned to roost in deep water, which makes them vulnerable to ambush. As they are less experienced, juvenile cranes may be notably more vulnerable to ambushes by bobcats.Kreger, M. D., Hatfield, J. S., Estevez, I., Gee, G. F., & Clugston, D. A. (2006). Behavioral profiles of the captive juvenile whooping crane as an indicator of post‐release survival. Zoo Biology: Published in affiliation with the American Zoo and Aquarium Association, 25(1), 11–24. 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. At least 12 bobcats have been trapped and relocated in an attempt to save the cranes.
In Florida, whooping cranes may be eaten by some growth stage of invasive snakes such as Burmese pythons, reticulated pythons, Southern African rock pythons, Central African rock pythons, boa constrictors, yellow anacondas, Bolivian anacondas, dark-spotted anacondas, and green anacondas.
Diet
These birds forage while walking in shallow water or in fields, sometimes probing with their bills. They are omnivorous but tend to be more inclined to animal material than most other cranes. Only the red-crowned crane may have a more carnivorous diet among living cranes.Meine, C., & Archibald, G. (Eds.). (1996). The cranes: status survey and conservation action plan. IUcN. In their Texas wintering grounds, this species feeds on various crustaceans, mollusks, grasshoppers, fish (such as eel), small reptiles (such as snakes), mice, voles, aquatic plants, acorns and fruits (such as wolfberry [Lycium carolinianum]). Potential foods of breeding birds in summer include frogs, snakes, small rodents, small birds, fish (such as minnows), aquatic insects, crayfish, clams, snails, aquatic tubers, and berries. Six studies from 1946 to 2005 have reported that blue crabs (Callinectes sapidus) are a significant food sourceNutritional Value of Winter Foods for Whooping Cranes
Jay T. Nelson, R. Douglas Slack and George F. Gee
The Wilson Bulletin
Vol. 108, No. 4 (Dec., 1996), pp. 728-739 (12 pages)
Published By: Wilson Ornithological Society for whooping cranes wintering at Aransas National Wildlife Refuge, constituting up to 90 percent of their energy intake in two winters; 1992–93 and 1993–94.
Waste grain, including wheat, barley, and corn, is an important food for migrating whooping cranes, but they do not swallow gizzard stones; they digest grain less efficiently than sandhill cranes.
Individual recognition, territorial and partnership fidelity
In earlier years, whooping crane chicks were caught and banded in the breeding areas of Wood Buffalo National Park. Although this delivered valuable insight into individual life history and behaviour, it has been discontinued due to risks to the cranes and the people involved.