White-bellied sea eagleIcthyophaga leucogaster出会える場所と時期

The white-bellied sea eagle is a powerful fish-eating raptor distributed from South Asia through Southeast Asia to Australia. Adults have a white head and underparts, gray upperwings and dark flight feathers, producing a striking pattern when seen overhead. Despite its name, it also occupies large inland waters. Coastal pairs depend on productive feeding areas and secure nest trees or other elevated sites, making disturbance and shoreline development important local concerns.

Size

70-85 cm long; wingspan 180-220 cm

Weight

2.5-4.5 kg

Lifespan

Not reliably established

Status

Least Concern

Pairs often patrol a territory by soaring, then wait on a prominent perch overlooking water. Prey is taken with the feet, sometimes in a low sweeping pass across the surface. These eagles also scavenge and steal food from other birds. Courtship can include coordinated flight displays, while breeding adults maintain bulky stick nests. Their loud, goose-like calls are surprisingly different from the piercing cries commonly associated with large eagles. Vocalizations are common and distinctive, often a loud, honking 'goose-like' call or a series of clanging notes. During hunting, they perform a shallow dive from a perch or while soaring, grasping prey with powerful talons without fully submerging.

• Females are generally larger than males.
• Its calls are often described as goose-like honks.
• It can take prey from other fishing birds through aerial harassment.
• Young birds are largely brown and acquire the clean adult pattern gradually.

Resident birds can be observed year-round where territories persist. Favor local dry or settled weather for shore watching, but do not interpret tourism seasons as nesting calendars. Breeding timing differs substantially between tropical Southeast Asia and Australia's temperate and tropical coastal regions. In tropical regions like Southeast Asia, breeding may occur throughout the year, peaking during the dry season when prey is more concentrated. In Australia, northern populations often breed in the dry season (April-October), while southern populations breed in the wet season (August-February).

Habitats include sea coasts, offshore islands, estuaries, mangroves, broad rivers and large lakes. Tall trees are important nesting and lookout structures in many regions, although cliffs may also be used. Extensive wetlands and relatively undisturbed shorelines can support resident pairs. Though adaptable, they generally avoid densely forested inland areas and arid zones. Their presence often indicates a healthy coastal or freshwater ecosystem, supporting diverse fish and prey populations.

Fish form a major part of the diet, but the species also takes waterbirds, reptiles and small mammals, and consumes carrion. Food may be captured directly, scavenged along shorelines or stolen from other hunters, depending on locally available opportunities. They are opportunistic predators, often taking a wide variety of fish species, marine snakes, and even sea turtles. Chicks are fed a diet of small, easily digestible prey items, gradually shifting to larger prey as they grow.

Common name

White-bellied sea eagle

Scientific name

Icthyophaga leucogaster

Animal group

Birds

Size

70-85 cm long; wingspan 180-220 cm

Weight

2.5-4.5 kg

Lifespan

Not reliably established

Status

Least Concern

Identification

Adults differ from the smaller brahminy kite in having gray rather than chestnut upperparts, a wedge-shaped white tail and much broader wings. Juveniles are largely brown with a streaky underside, gradually acquiring the adult white head and underparts over several years. Their broad, 'plank-like' wings are held in a slight 'V' shape when soaring, distinguishing them from other large raptors.