Friday, 7 November 2014

The Siberian crane – Migratory bird

The Siberian crane – Migratory bird 




The Siberian Crane is a very distinctive member of the crane family with regards to their structure, home ground and behavior. The Siberian Crane is characterized by white plumage, red or pale yellow eyes, reddish pink toes or legs. The face and sides of the head are brick red in colour and they do not have any feathers. It is very difficult to distinguish between the male and the female. The point of distinction is that the former is larger in size and have longer beaks. They are omnivorous and eat fishes and insects as well. The Siberian Cranes nest in western Siberia and migrate to India. The migration route stretches for 4000 miles. The Siberian Crane is presently an endangered species. Larger numbers of birds have been hunted over the years. 


The Siberian crane / Siberian white crane or the snow crane, is a  distinctive among the cranes, adults are nearly all snowy white, except for their black primary feathers that are visible in flight and with two breeding populations in the Arctic tundra of western and eastern Russia. The 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.


Adults of both sexes have a pure white plumage except for the black primaries, alula and primary coverts. 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. During breeding season, both the male and female cranes are often seen with mud streaking their feathers. They dip their beaks in mud and smear it on their feathers. The call is very different from the trumpeting of most cranes and is a goose-like high pitched whistling toyoya. They typically weigh 4.9–8.6 kg (10.8–19 lbs) and stand about 140 cm (55 in) tall. The wingspan is 210–230 cm (83–91 in) and length is 115–127 cm (45–50 in). Males are on average larger than females. There is a single record of an outsized male of this species weighing 15 kg (33 lb). The breeding area of the Siberian crane formerly extended between the Urals and Ob river south to the Ishim and Tobol rivers and east to the Kolyma region. The populations declined with changes in land use, the draining of wetlands for agricultural expansion and hunting on their migration routes.
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. 
These snow 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.


The status of this crane is critical and the world population is estimated to be around 3200–4000, nearly all of them belonging to the eastern breeding population. Of the 15 crane species this is the most threatened. Historic records from India suggest a wider winter distribution in the past including records from Gujarat, near New Delhi and even as far east as Bihar.



2 comments:

  1. a few photos that you have posted for Siberian cranes are actually White storks

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  2. The top photograph in your essay is an European White Stork (Ciconia ciconia), not a Siberian Crane (Leucogeranus leucogeranus).
    DML

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