White-breasted sea eagle, White-bellied fish-hawk, White-eagle, Grey-backed sea eagle
The White-bellied sea eagle (Haliaeetus leucogaster) is a large diurnal bird of prey. Originally described by Johann Friedrich Gmelin in 1788, it is closely related to Sanford's sea eagle of the Solomon Islands, and the two are considered superspecies. The White-bellied sea eagle is revered by indigenous people in many parts of Australia, and is the subject of various folk tales throughout its range.
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DiurnalDiurnal animals are active during the daytime, with a period of sleeping or other inactivity at night. The timing of activity by an animal depends ...
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CarnivoreA carnivore meaning 'meat eater' is an organism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of a...
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PiscivoresA piscivore is a carnivorous animal that eats primarily fish. Piscivorous is equivalent to the Greek-derived word ichthyophagous. Fish were the die...
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TerrestrialTerrestrial animals are animals that live predominantly or entirely on land (e.g., cats, ants, snails), as compared with aquatic animals, which liv...
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ArborealArboreal locomotion is the locomotion of animals in trees. In habitats in which trees are present, animals have evolved to move in them. Some anima...
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AltricialAltricial animals are those species whose newly hatched or born young are relatively immobile. They lack hair or down, are not able to obtain food ...
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Apex predatorAn apex predator, also known as a top predator, is a predator at the top of a food chain and has no natural predators. These animals usually occup...
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GlidingGliding flight is heavier-than-air flight without the use of thrust and is employed by gliding animals. Birds in particular use gliding flight to m...
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TerritorialA territory is a sociographical area that which an animal consistently defends against the conspecific competition (or, occasionally, against anima...
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OviparousOviparous animals are female animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive...
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NomadicNomadic animals regularly move to and from the same areas within a well-defined range. Most animals travel in groups in search of better territorie...
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CongregatoryCongregatory animals tend to gather in large numbers in specific areas as breeding colonies, for feeding, or for resting.
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Soaring birdsSoaring birds can maintain flight without wing flapping, using rising air currents. Many gliding birds are able to "lock" their extended wings by m...
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MonogamyMonogamy is a form of relationship in which both the male and the female has only one partner. This pair may cohabitate in an area or territory for...
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Generally solitaryGenerally solitary animals are those animals that spend their time separately but will gather at foraging areas or sleep in the same location or sh...
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Not a migrantAnimals that do not make seasonal movements and stay in their native home ranges all year round are called not migrants or residents.
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starts withThe White-bellied sea eagle has a white head, rump and underparts, and dark or slate-grey 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-grey with a darker tip, and the irides are dark brown. The cere is also lead grey. The legs and feet are yellow or grey, with long black talons (claws). Unlike those of eagles of the genus Aquila, the legs are not feathered. The sexes are similar but like many raptors, the female is larger than the male. 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.
White-bellied sea eagles are found regularly from Mumbai 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, they are restricted to Nissan Island. These birds occur mainly in coastal areas, islands, and estuaries but also in large inland water bodies, lakes, rivers, and wetlands. They usually breed near the water with some forest cover or in rocky areas.
White-bellied sea eagles are generally territorial; some birds form permanent pairs that inhabit territories throughout the year, while others are nomadic. Immature birds are generally dispersive, with many moving over 50 km (31 mi) away from the area they were raised. These birds are diurnal and often seen perched high in a tree or soaring over waterways and adjacent land. They spend time singly or in pairs. Small groups of White-bellied sea eagles sometimes gather if there is a plentiful source of food such as a carcass or fish offal on a ship. A pair may cooperate to hunt. During hunting the bird prepares for the strike by holding its feet far forward (almost under its chin) and then strikes backward while simultaneously beating its wings to lift upwards. They often catch a fish by flying low over the water and grasping it in its talons. Generally, only one foot is used to seize prey. White-bellied sea eagles may also dive at a 45-degree angle from their perch and briefly submerge to catch fish near the water's surface. These large birds of prey have a loud goose-like honking call which is heard particularly during the breeding season; pairs often honk in unison and often carry on for some time when perched. The male's call is higher-pitched and more rapid than that of the female.
White-bellied sea eagles are opportunistic carnivores and consume a wide variety of animal prey, including carrion. They hunt mainly aquatic animals, such as fish, turtles, and sea snakes, but they will also take birds, such as little penguins, Eurasian coots, and shearwaters, and mammals (including flying foxes) as well. White-bellied eagles feed on carrion such as dead sheep, birds, and fish found along the waterline, as well as raiding fishing nets and following cane harvesters.
White-bellied sea eagles are monogamous; pairs remain together until one bird dies, after which the surviving bird quickly seeks a new mate. The breeding season varies according to location - it occurs in the dry season in Papua New Guinea, and from June to August in Australia. During this time a pair of White-bellied sea eagles perform skillful displays of flying such as diving, gliding, and chasing each other while calling loudly. They may mirror each other, flying 2-3 m (6.6-9.8 ft) apart and copying each other swooping and swerving. They also perform a talon-grappling display 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. These birds usually choose tall trees or man-made pylons to nest in. The nest is a large deep bowl constructed of sticks and branches and lined with such materials as grass or seaweed. Nests are generally sited in the forks of large trees overlooking bodies of water. Cliffs are also suitable nesting sites, and on islands, nests are sometimes built directly on the ground. The female usually lays a clutch of 2 dull, white, oval eggs that are incubated over 6 weeks before hatching. Eaglets are covered in white down when they emerge from the egg. Although 2 eggs are laid, it is unusual for both chicks to be reared successfully to fledging (leaving the nest). One egg may be infertile, or the second chick may die in the nest. If the first clutch is lost, the parents may attempt a second brood. Eaglets usually fledge when they are 70 to 80 days old, and remain around the parents' territory for up to 6 months or until the following breeding season. White-bellied sea eagles start breeding at around 6 years of age.
Although not threatened globally, White-bellied sea eagles have declined in parts of southeast Asia such as Thailand, and southeastern Australia. Human disturbance to their habitat is the main threat, both from direct human activity near nests which impacts breeding success and from the removal of suitable trees for nesting. In Tasmania, these birds are 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.
According to the IUCN Red List, the total White-bellied sea eagle population size is around 1,000-10,000 individuals, which is around 670-6,700 mature individuals. The population in China has been estimated at around 100-10,000 breeding pairs. Currently, this species is classified as Least Concern (LC) on the IUCN Red List, and its numbers today are decreasing.
Being apex predators in their ecosystem, White-bellied sea eagles control populations of many species of fish, birds, mammals, and reptiles.
