The Sandhill Crane Grus canadensis is a large crane of North America and extreme northeastern Siberia. The common name of this bird references habitat like that at the Platte River, on the edge of Nebraska’s Sandhills in the American midwest. This is the most important stopover area for the Lesser Sandhill Crane, Grus (canadensis) canadensis, with up to 450,000 of these birds migrating through annually.
Adults are gray overall; during breeding, the plumage is usually much worn and stained, particularly in the migratory populations, and looks nearly ochre. They have a red forehead, white cheeks and a long dark pointed bill. They have long dark legs which trail behind in flight and a long neck that is kept straight in flight. Immature birds have reddish brown upper parts and gray underparts. The sexes look alike. Size varies among the different subspecies. This crane frequently gives a loud trumpeting call that suggests a French-style “r” rolled in the throat.
The only other large grayish-bodied bird of North America is the Great Blue Heron. Although this heron is of similar dimensions to the Sandhill Crane and is sometimes mistakenly called a crane, even though it is very different in plumage details and build, and like other herons it flies with its neck tucked towards the body in a flat “S”-shape.
The sandhill crane’s large wingspan (up to 6 1/2 feet) makes this a very skilled soaring bird similar in style to hawks and eagles. Utilizing thermals to obtain lift, they can stay aloft for many hours, requiring only occasional flapping of their wings and consequently expending little energy. With migratory flocks containing 100’s of birds or more, they can create clear outlines of the normally invisible rising columns of air (thermals) which they ride.
Although it is rare, some Sandhill Cranes have been spotted devouring their young. If the mated pair recognizes a weakness in the young colt, they immediately seize their young and eat them. Although it is a rare habit it has been noted in special circumstances.
The Sandhill Crane has one of the longest fossil histories of any extant bird. A 10-million-year-old crane fossil from Nebraska is often cited as being of this species, but this is more likely from a prehistoric relative or the direct ancestor of the Sandhill Crane and may not belong in the genus Grus. The oldest unequivocal Sandhill Crane fossil is “just” 2.5 million years old, over one and a half times older than the earliest remains of most living species of birds, which are primarily found from after the Pliocene/Pleistocene boundary some 1.8 million years ago. As these ancient Sandhill Cranes varied as much in size as the present-day birds, even those Pliocene fossils were sometimes described as new species. Grus haydeni on the other hand may or may not have been a prehistoric relative of the living species, or it may actually comprise material of the Sandhill Crane and its ancestor.
Their breeding habitat is marshes and bogs in central and northern Canada, Alaska, part of the midwestern and southeastern United States, Siberia and Cuba. They nest in marsh vegetation or on the ground close to water. The female lays two eggs on a mound of vegetation, but it is rare that both chicks hatch and grow to independence. Cranes mate for life; both parents feed the young, called “colts”, who are soon able to feed themselves. The Sandhill Crane does not breed until it is two to seven years old, and the average generation time is 12.5 years. It can live up to 25 years in the wild; in captivity it has been known to live more than twice that span. Mated pairs stay together year-round and migrate south as a group with their offspring.
Eggs and nestling cranes are eaten by crows, ravens, canids, hawks, eagles, and raccoons. Adult cranes are preyed on by foxes, coyotes, eagles, wolves, bobcats, and large owls. When approached by an avian predator, sandhill cranes will fly at the predator, kicking at it with their feet. When aware of a mammalian predator, sandhill cranes move toward the predator with their wings spread and their bill pointed at the predator. If the predator persists, sandhill cranes will attack, hissing, stabbing with their bills and kicking with their feet. The cranes tend to be more aggressive while protecting their young. Mammalian predators are generally more likely to prey on adult cranes while they are distracted by nesting.
These birds forage while walking in shallow water or in fields, sometimes probing with their bills. They are omnivorous, eating insects, aquatic plants and animals, rodents, seeds and berries. Outside of the nesting season, they forage in large flocks, often in cultivated areas. In many western states and provinces of Canada, Sandhill Cranes are hunted during waterfowl seasons. The meat is reportedly among the better-tasting game birds.
The Florida subspecies is often seen in residential yards, and these birds seem little afraid of human approach. These visitors will eat shelled corn and commercially purchased bird seed from the ground and from feeders. They may be seen in yards in north-central Florida virtually year-round, often in pairs that may be accompanied by a juvenile.
Though the Sandhill Crane is not considered threatened as a species, the three southernmost subspecies are quite rare. While the migratory birds could at least choose secure breeding habitat, the resident populations could not, and many subpopulations were destroyed by hunting or habitat change. However, initially the Greater Sandhill crane proper suffered most from persecution; by 1940 probably fewer than 1,000 birds remained. They have since increased greatly again, though with nearly 100,000 individuals they are still less plentiful than the Lesser Sandhill Crane, which numbers over 400,000 individuals, making the species the most plentiful crane alive today.
The Florida Sandhill Crane is far less common, with some 5,000 individuals remaining. They are most threatened by habitat destruction and probably depend on human management in the long run. In Florida, it is protected, and if killed, carries a very high monetary penalty. This subspecies is under protection of state and federal law at this time. Since the loss of habitat is a somewhat controllable cause of a declining population, habitat preservation is a valuable management measure. The current outlook for the Florida sandhill crane, if it can be maintained on the protected habitats, is good. Transplanting wild birds, as well as introducing captive-reared birds into suitable areas where crane numbers are low, appears to be a viable technique in the management of this threatened species. It is hoped that these management strategies, plus continued ecological research, will prevent the Florida sandhill crane from reaching a more critical status.
The Mississippi Sandhill Crane has most drastically declined in range; it used to occur along most of the northern Gulf of Mexico coast and its range was at one time nearly parapatric with that of its eastern neighbor (compare the Mottled Duck); today only some 150 remain in an intensively managed population, but this seems at least stable in recent times. Some 300 Cuban Sandhill Cranes remain; this is the least-known of the populations.10
The Mississippi Sandhill Crane has become the first bird to have a young hatched where an egg was fertilized by a sperm that was previously thawed out from a cryogenic state. This occurred at the Audubon Institute as part of this subspecies’ Recovery Plan.
Sandhill Cranes have been used as foster parents for Whooping Crane eggs and young in reintroduction schemes for that species. This project failed as these foster-raised Whooping Cranes imprinted on their foster parents and later did not recognize other Whooping Cranes as their conspecifics – attempting instead, unsuccessfully, to pair with Sandhill Cranes. Wikipedia
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