Sarus Crane, Bird

The sarus crane (Grus antigone) is a large non-migratory crane found in parts of the Indian Subcontinent, Southeast Asia and Australia. The tallest of the flying birds, standing at a height of up to 1.8 m (5.9 ft),they are conspicuous and iconic species of open wetlands. The sarus crane is easily distinguished from other cranes in the region by the overall grey colour and the contrasting red head and upper neck. They forage on marshes and shallow wetlands for roots, tubers, insects, crustaceans and small vertebrate prey. Like other cranes, they form long-lasting pair-bonds and maintain territories within which they perform territorial and courtship displays that include loud trumpeting, leaps and dance-like movements. In India they are considered symbols of marital fidelity, believed to mate for life and pine the loss of their mates even to the point of starving to death. The main breeding season is during the rainy season, when the pair builds an enormous nest "island", a circular platform of reeds and grasses nearly two metres in diameter and high enough to stay above the shallow water surrounding it. Sarus crane numbers have declined greatly in the last century and it has been estimated that the current population is a tenth or less (perhaps 2.5%) of the numbers that existed in the 1850s. The stronghold of the species is India, where it is traditionally revered and lives in agricultural lands in close proximity to humans. Elsewhere, the species has been extirpated in many parts of its former range.

The adult sarus crane is very large with grey wings and body; a bare red head and part of the upper neck; a greyish crown; and a long greenish-grey pointed bill. In flight, the long neck is held straight, unlike that of an heron, which folds it back, and the black wing tips can be seen; the crane's long pink legs trail behind them. This bird has a grey ear covert patch, an orange-red iris and a greenish-grey bill. Juveniles have a yellowish base to the bill and the brown-grey head is fully feathered.

The bare red skin of the adult's head and neck is brighter during the breeding season. This skin is rough and covered by papillae, and a narrow area around and behind the head is covered by black bristly feathers. The sexes do not differ in plumage although males are on average larger than females; male Sarus of the Indian population can attain a maximum height of about 180 cm (5.9 ft) making them the world's tallest extant flying bird. The weight of nominate race individuals is 6.8–7.8 kg (16 lb), while five adult sharpii averaged 8.4 kg (18.5 lb). Across the distribution range, the 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 250 cm (87–100 in). Birds from Australia tend to be smaller than birds from the north.

In Australia, the Sarus can easily be mistaken for the more widespread Brolga. The Brolga has the red colouring confined to the head and not extending into the neck

The species has historically been widely distributed on the lowlands of India along the Gangetic plains, extending south to the Godavari River, west to coastal Gujarat, the Tharparkar District of Pakistan, and east to West Bengal and Assam. The species no longer breeds in the Punjab, though it winters regularly. Sarus cranes are rare and occur in very low numbers in West Bengal and Assam, and are no longer found in the state of Bihar. In Nepal, its distribution is restricted to the western lowland plains, with most of the population occurring in Rupandehi, Kapilvastu, and Nawalparasi districts.

There are two distinct populations of sarus cranes in South-east Asia: the northern population in China and Burma, and the southern population in Cambodia and Vietnam. The Sarus used to extend to Thailand and further east into the Philippines, but became extinct. In 2011, captive bred cranes were reintroduced into Thailand.In Australia they are found only in the northern parts, and are partly migratory in some areas.The global range has shrunk and the largest occupied area is now in India. With marshlands largely destroyed, these cranes are increasingly dependent on wet paddy fields in India. Although now found mainly at a low elevation on the plains, there are some historical records from highland marshes further north in Harkit Sar and Kahag in Kashmir. The sarus crane breeds in some high elevation regions such as near the Pong Dam in Himachal Pradesh, where populations may be growing in response to increasing rice cultivation along the reservoir. In rice-dominated districts of Uttar Pradesh, sarus crane abundance (estimated as occupancy) was highest in the western districts, intermediate in the central districts, and minimal in the eastern districts. Sarus crane abundance was positively associated with percentage of wetlands on the landscape, and negatively with the percentage of area under rice cultivation.

Two isolated populations exists in Australia, one from the western Kimberley region east to Arnhem Land in the Northern Territory and another population from Burketown eastwards and as far south as Townsville. Sarus cranes are not found on the Cape York Peninsula north of Weipa. They are commonly seen in Kakadu National Park, where the species is often hard to find among the more numerous Brolga, and on the Atherton Tablelands in Queensland.

Sarus cranes preferentially use wetlands or uncultivated patches amid flooded rice paddies (locally called khet-taavadi) for nesting in India. Breeding pairs are territorial and prefer to forage in natural wetlands, though wet crops like rice and wheat are also frequented.

Ecology and behaviour

Unlike many other cranes that make long migrations, the sarus crane is largely non-migratory; it may however make short-distance movements in response to rain or dry weather conditions. The only migratory population is in South-east Asia.Breeding pairs maintain territories that are defended from other cranes using a large repertoire of calls and displays. Non-breeding birds occur as flocks of various sizes that vary from 1–430 birds. In semi-arid areas, breeding pairs and successfully fledged juveniles depart from territories in the dry season and join non-breeding flocks. In areas with perennial water supply, like in the western plains of Uttar Pradesh, breeding pairs maintain perennial territories. The largest known flocks are from the 29 km2 Keoladeo National Park – as many as 430 birds, and from wetlands in Etawah and Mainpuri districts in Uttar Pradesh, ranging from 245–412 birds. Flocks of over 100 birds are also regularly reported from Gujarat and Australia. During the breeding season, breeding pairs displace non-breeding birds from some wetland sites, and local populations can appear to decline. Sarus crane populations in Keoladeo National Park have been noted to reduce from over 400 birds in summer to just 20 birds during the Monsoon.

They roost in shallow water, where they may be safe from some ground predators. Adult birds do not moult their feathers annually and replace them only once every two or three years.

Feeding

Sarus cranes forage in shallow water (usually with less than 30 cm (1 ft) depth of water) or in fields, frequently probing in mud with their long bills. They are omnivorous, eating insects (especially grasshoppers), aquatic plants, fish (perhaps only in captivity), frogs, crustaceans and seeds. Occasionally tackling larger vertebrate prey such as water snakes (Xenochrophis piscator), Sarus cranes may in rare cases feed on the eggs of birds and turtles. Plant matter eaten includes tubers, corms of aquatic plants, grass shoots as well as seeds and grains from cultivated crops such as groundnuts and cereal crops such as rice.[