White-bellied Sea Eagle

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Image:WBSeaEagle.jpg

Common Name: White-bellied Sea Eagle
Scientific Name: Haliaeetus leucogaster

Size: 26-36 inches (66-90 cm); Wingspan: 68-86 inches (178-220 cm)

Habitat: Asia and Australia; it is found regularly from Mumbai (sometimes north to Gujarat, and in the past in the Lakshadweep Islands) eastwards in India, Bangladesh, and Sri Lanka in southern Asia, through all of coastal Southeast Asia including Burma, Thailand, Malaysia, Indonesia, Indochina, the main and offshore islands of the Philippines, and southern China including Hong Kong, Hainan and Fuzhou, eastwards through New Guinea and the Bismarck Archipelago, and Australia. In the northern Solomons it is restricted to Nissan Island, and replaced elsewhere by Sanford's sea eagle. In Victoria, where it is otherwise scarce, it is locally more common at Corner Inlet and Gippsland Lakes. Similarly in South Australia, it is most abundant along the north coast of Kangaroo Island. The range extends to the islands of Bass Strait and Tasmania, and it is thought able to move between the islands and the mainland. There is one unconfirmed record from Lord Howe Island and several from New Zealand.

Status: Least Concern. Global population: 10,000-100,000 adult individuals with a declining population trend. They have become rare in Thailand and some other parts of southeast Asia. A field study on Kangaroo Island in South Australia has shown that nesting pairs in areas of high human disturbance (as defined by clearing of landscape and high human activity) had lower breeding success rates.

The white-bellied sea eagle is listed under the marine and migratory categories which give it protected status under Australia's federal Environment Protection and Biodiversity Conservation Act 1999. As a mainly coastal species, it is vulnerable to habitat destruction in Australia's increasingly populated and urbanized coastal areas, particularly in the south and east of the country, where it appears to have declined in numbers. However, there may have been an increase in population inland, secondary to the creation of reservoirs, dams and weirs, and the spread of the introduced common carp (Cyprinus carpio). However, it is rare along the Murray River where it was once common. It is also listed as Threatened under Victoria's Flora and Fauna Guarantee Act (1988), with possibly fewer than 100 breeding pairs remaining in the state. On the 2007 advisory list of threatened vertebrate fauna in Victoria, the white-bellied sea eagle is listed as vulnerable.

There are fewer than 1000 adult birds in Tasmania, where the species is listed as Vulnerable under Schedule 3.1 of the Tasmanian Threatened Species Protection Act 1995. In Tasmania it is threatened by nest disturbance, loss of suitable nesting habitat, shooting, poisoning, trapping, and collision with power lines and wind turbines, as well as entanglement and environmental pollution. Estuaries are a favored habitat, and these are often subject to environmental disturbance. White-bellied sea eagles have been observed to increase their hunting ranges to include salmon fish farms, but the effect of this on breeding success is unknown.

Diet: Mainly aquatic animals, such as fish, turtles and sea snakes, but it takes birds, such as little penguins, Eurasian coots and shearwaters, and mammals as well. They may even steal food from their own species, including their mates.

It usually catches a fish by flying low over the water and grasping it in its talons. It prepares for the strike by holding its feet far forward (almost under its chin) and then strikes backwards while simultaneously beating its wings to lift upwards. Only one foot is used to seize prey.

The white-bellied sea eagle may also dive at a 45 degree angle from its perch and briefly submerge to catch fish near the water surface. While hunting over water on sunny days, it often flies directly into the sun or at right angles to it, seemingly to avoid casting shadows over the water and hence alerting potential prey.

Nesting: The sexes are similar with females being slightly larger. Adults have a white head, rump and underparts, and dark or slate-gray back and wings. In flight, the black flight feathers on the wings are easily seen when the bird is viewed from below. The large, hooked bill is a leaden blue-gray with a darker tip, and the irides are dark brown. The cere is also lead gray. The legs and feet are yellow or gray, with long black talons (claws). Unlike those of eagles of the genus Aquila, the legs are not feathered. The sexes are similar. The molting pattern of the white-bellied sea eagle is poorly known. It appears to take longer than a year to complete, and can be interrupted and later resumed from the point of interruption. A young white-bellied sea eagle in its first year is predominantly brown, with pale cream-streaked plumage on their head, neck, nape and rump areas. The plumage becomes more infiltrated with white until it acquires the complete adult plumage by the fourth or fifth year.The species breeds from around six years of age onwards. The lifespan is thought to be around 30 year.

The breeding season varies according to location. A pair of white-bellied sea eagles performs skillful displays of flying before copulation: diving, gliding and chasing each other while calling loudly. They may mirror each other, flying 2–3 m (7–10 ft) apart and copying each other swooping and swerving. A talon-grappling displays where the pair will fly high before one flips upside down and tries to grapple the other's talons with its own. If successful, the two then plunge cartwheeling before separating as they approach the ground.This behavior has also been recorded as an aggressive display against a wedge-tailed eagle.

They usually choose tall trees or man-made pylons to nest in with good visibility to survey the surrounding area. The nest is a large deep bowl constructed of sticks and branches, and lined with such materials as grass or seaweed. Yearly renovations result in nests getting gradually bigger. Nests are built in the forks of large trees overlooking bodies of water. Old nests of wedge-tailed eagles or whistling kites have been renovated and used. Cliffs are also suitable nesting sites, and on islands nests are sometimes built directly on the ground. A breeding pair, with the male being more active, spends three to six weeks building or renovating the nest before laying eggs. Normally a clutch of two dull, white, oval eggs are laid and are incubated over six weeks before hatching. The young are semi-altricial, and covered in white down when they emerge from the egg. Initially, the male brings food and the female feeds the chicks, but both parents feed the chicks as they grow larger. Although two eggs are laid, it is unusual for two young to be reared successfully to fledging. One of the eggs is sometimes infertile or the second chick dies before fledging. If the first clutch is lost, the parents may attempt a second brood. Nestlings fledge when 70 to 80 days old, and remain around the parents' territory for up to six months or until the following breeding season.

Cool Facts: The white-bellied sea eagle was important to different tribes of indigenous people across Australia. The guardian animal of the Wreck Bay aboriginal community, it is also the official emblem of the Booderee National Park and Botanic Gardens in the Jervis Bay Territory. Known as Manulab to the people of Nissan Island, the white-bellied sea eagle is considered special and killing it is forbidden. Its calls at night are said to foretell danger, and seeing a group of calling eagles flying overhead is a sign that someone has died. Local Malay folk tales tell of the white-bellied sea eagle screaming to warn the shellfish of the turning of tides, and a local name burung hamba siput translates as "slave of the shellfish". Called Kaulo in the recently extinct Aka-Bo language, the white-bellied sea eagle was held to be the ancestor of all birds in one Andaman Islands folk tale.

The white-bellied sea eagle is also featured on the $10,000 Singapore note and is the emblem of the Manly-Warringah Sea Eagles rugby league team.


Found in Songbird ReMix Birds of Prey Volume 5: Falcons, Hawks & Eagles

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