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The Siberian Crane (Grus leucogeranus) also known as the Siberian White Crane or theSnow Crane, is a bird of the family Gruidae, the cranes. They are distinctive among the cranes, adults are nearly all snowy white, except for their black primary feathers that are visible in flight and a naked red face, with two breeding populations in the Arctic tundra of western and eastern Russia. They eastern populations migrate during winter to China while the western population winters in Iran and formerly, in India. Among the cranes, they make the longest distance migrations. Their populations, particularly those in the western range have declined drastically in the 20th century due to hunting along their migration routes and habitat degradation. The world population was estimated in 2010 at about 3200 birds, mostly belonging to the eastern population with about 95% of them wintering in the Poyang lake basin in China, a habitat that may be altered by the Three Gorges Dam.
Description
Adults of both sexes have a pure white plumage except for the black primaries, alula and primarycoverts.The forecrown, face and side of head is bare and brick red, the bill is dark and the legs are pinkish. The iris is yellowish. Juveniles are feathered on the face and the plumage is dingy brown. There are no elongated tertial feathers as in some other crane species. The call is very different from the trumpeting of most cranes and is a goose-like high pitched whistling toyoya. They are about 4.9-8.6 kg (10.8-19 lbs) in weight and stand about 140 cm (55 in) tall with a 210–230 cm (83–91 in) wing span. Males are on average larger than females.
Feeding
These cranes feed mainly on plants although they are omnivorous. In the summer grounds they feed on a range of plants including the roots of hellebore (Veratrum misae), seeds of Empetrum nigrum as well as small rodents (lemmings and voles), earthworms and fish. They were earlier thought to be predominantly fish eating on the basis of the serrated edge to their bill, but later studies suggest that they take animal prey mainly when the vegetation is covered by snow. They also swallow pebbles and grit to aid in crushing food in their crop. In their wintering grounds in China, they have been noted to feed to a large extent on the submerged leaves of Vallisneria spiralis.[15] Specimens wintering in India have been found to have mainly aquatic plants in their stomachs. They are however noted to pick up beetles and birds eggs in captivity.
Breeding
Siberian Cranes return to the Arctic tundra around the end of April and beginning of May. The nest is usually on the edge of lake in boggy ground and is usually surrounded by water. Most eggs are laid in the first week of June when the tundra is snow free. The usual clutch is two eggs, which are incubated by the female after the second egg is laid. The male stands guard nearby. The eggs hatch in about 27 to 29 days. The young birds fledge in about 80 days. Usually only a single chick survives due to aggression between young birds. The population increase per year is less than 10%, the lowest recruitment rate among cranes. Their success in breeding may further be hampered by disturbance from reindeer and sometimes dogs that accompany reindeer herders. Captive breeding was achieved by the International Crane Foundation at Baraboo after numerous failed attempts. Males often killed their mates and captive breeding was achieved by artificial insemination and the hatching of eggs by other crane species such as the Sandhill and using floodlights to simulate the longer daylengths of the Arctic summer.
Migration
This species breeds in two disjunct regions in the arctic tundra of Russia; the western population along the Ob in Yakutia and western Siberia. It is a long distance migrant and among the cranes, makes the longest migrations. The eastern population winters on the Yangtze River and Lake Poyang in China, a western population formerly wintered at Keoladeo National Park, India but was extirpated, the last crane in this population was observed in 2002. The west and the western population in Fereydoon Kenar in Iran
