Sarus Crane

[sahr-uhs]

The Sarus Crane, Grus antigone is an all-year resident breeding bird in northern Pakistan and India (especially Central India and the Gangetic plains), Nepal, Southeast Asia and Queensland, Australia. It is a very large crane, averaging 156 cm (5 ft) in length, which is found in freshwater marshes and plains.

Description

Adults are grey with a bare red head and white crown and a long dark pointed bill. In flight, the long neck is kept straight, unlike herons, and the black wing tips can be seen; their long red or pink legs trail behind them. The sexes do not differ in color, but young birds are duller and browner. On average the male is larger than the female; Indian males can attain a maximum height of approximately 200 cm (6.6 ft), with a wingspan of 250 cm (8.5 ft), making them the world's tallest living flying bird. The average weight is 6.3-7.3 kg (14-16 lbs), so they are lighter-weight than Red-crowned Cranes. Across the range, weight can vary from 5 to 12 kg (11-26 lbs), height typically from 115 to 167 cm (45-69 in) and the wingspan from 220 to 280 cm (87-110 in). Birds from Australia tend to be smaller than birds from the north.

In Australia, the Sarus can easily be mistaken for the Brolga. The Brolga has a more widespread distribution across Australia, and its red colouring is confined to the head.

Ecology and behaviour

These birds are usually seen in small groups of 2-5 and they forage while walking in shallow water or in fields, sometimes probing with their long bills. They are omnivorous, eating insects, aquatic plants and animals, crustaceans, seeds and berries, small vertebrates, and invertebrates.

It nests on the ground, laying two to three eggs in a bulky nest. Unlike many cranes which make long migrations, the Sarus Crane does not; there is some short-distance dispersal however. Both the male and female take turns sitting on the nest, and the male is the main protector. They tend to mate for life.

Subspecies

There are up to four subspecies recognized; the nominal form from the Indian subcontinent being most strongly differentiated in having a white collar below the bare head and upper neck, and white tertiary remiges. These areas are grey in the other forms, of which the Indochina subspecies sharpei is smaller than Indian birds, the Australian gilliae smaller still and the birds once found on Luzon, Philippines being smallest of all.

Whether these forms are all well-established subspecies is somewhat disputed. Thorough mtDNA analyses, although hampered by the small number of available specimens, suggest that the continental Asian populations had ongoing gene flow until the 20th century range reductions, and that Australia was colonized by this species only in the Late Pleistocene, some 35.000 years ago (Wood & Krajewsky 1996). This is corroborated by nDNA microsatellite analyses with 4 times the sample size (Jones et al. 2005).

Furthermore, the latter analysis suggests that the Australian population is quite inbred. As there existis the possibility of (limited) hybridization with the genetically quite distinct Brolga, the Australian Sarus Crane can be expected to get well underway to becoming a genetically distinct species in the future. Jones et al. conclude that each of the 3 major surviving populations should be considered ESUs.

Conservation status

There were about 20.000 mature Sarus Cranes left in the wild in 2006 (BLI 2006a, b). The Indian population is less than 10,000 birds; it used to be found on occasion in Pakistan, but not anymore since the late 1980s, and it appears to be decreasing altogether (BLI 2006b). While the Australian population is higher than 5,000 birds and may be increasing (Jones et al. 2005, BLI 2006b), the Southeast Asian subspecies has been decimated by war and habitat modification and destruction (such as intensive agriculture and draining of wetlands) and by the mid-20th century had disappeared from large parts of its range which once stretched up to southern China; some 1500–2000 birds are left in several fragmented subpopulations . The little-known Philippine population is completely extinct since the late 1960s.

As a species, the Sarus crane is classified as Vulnerable (A2cde + 3cde). This means that the global population has declined by about a third since 1980, and is expected to continue to do so until the late 2010s. Threats constitute habitat destruction and/or degradation, hunting and collecting, as well as environmental pollution and possibly diseases or competing species. Inbreeding effects should be monitored in the Australian population (Jones ''et al.' 2005).

The species has been extirpated in Malaysia, Philippines and Thailand.

Popular culture

The species is venerated in India and legend has it that Valmiki cursed a hunter for killing a Sarus Crane and was then inspired to write the epic Ramayana

Media

References

Database entry includes a range map and justification for why this species is vulnerable.

BirdLife International (BLI) (2006b): Species Factsheet: Grus antigone Retrieved 2007-FEB-22.

Grimmett, Richard; Inskipp, Carol, Inskipp, Tim & Byers, Clive (1999): Birds of India, Pakistan, Nepal, Bangladesh, Bhutan, Sri Lanka, and the Maldives. Princeton University Press, Princeton, N.J.. ISBN 0-691-04910-6

Jones, Kenneth L.; Barzen, Jeb A. & Ashley, Mary V. (2005): Geographical partitioning of microsatellite variation in the sarus crane. Animal Conservation 8(1): 1–8. (HTML abstract)

Matthiessen, Peter & Bateman, Robert (2001): The Birds of Heaven: Travels with Cranes. North Point Press, New York. ISBN 0-374-19944-2

Wood, T.C. & Krajewsky, C. (1996): Mitochondrial DNA sequence variation among the subspecies of Sarus Crane (Grus antigone). Auk 113(3): 655–663. PDF fulltext