White-bellied sea eagle

White-bellied sea eagle - burrumering

What is a white-bellied sea eagle?

Most often seen with wings outspread soaring high in the sky above a waterway, white-bellied sea eagles are raptors. ‘Raptors’ are large birds of prey. 

White-bellied sea eagles are apex predators that nest in tall trees by waterways mainly feeding on fish and other aquatic animals. ‘Apex’ means they are at the top of the food chain or food web. 

Burrumering is the name for an eagle used by the Darug people of the Sydney basin. The distinctive white belly of these sea eagles distinguishes them from other eagles and large birds of prey. They are also known as white-breasted sea eagles. Their scientific name is Haliaeetus leucogaster. Haliaeetus is a Latin word – hali meaning sea and aetos meaning eagle. Leucogaster is a Greek word – leuco meaning white and gaster meaning belly or stomach.

What do white-bellied sea eagles look like?

Adult white-bellied sea eagles have a dark grey back and a white head, chest and belly. Viewed from underneath when in flight, the upper parts of their wings are white. They have a short wedge-shaped tail with white-tipped tail feathers. 

The adult is 75 to 85 centimetres tall and has a wingspan of 1.8 to 2 metres. Juvenile white-bellied sea eagles have a brown chest that becomes mottled as their white plumage comes through. ‘Plumage’ means feathered covering.

As with all eagles, white-bellied sea eagles have a large hooked beak and strong feet with long toes and long curved talons. ‘Talons’ are claws. The feet are cream, the beak is grey and the tip of the beak and talons are black.

What do white-bellied sea eagles sound like?

During the breeding season white-bellied sea eagles make a honking call. Pairs may call in a duet.

Where do white-bellied sea eagles live?

White-bellied sea eagles live along the coasts of mainland Australia and Tasmania. They inhabit coastal and inland water bodies and shorelines such as seashores, lakes, lagoons, rivers and estuaries. An ‘estuary’ is a water body in which freshwater and tidal saltwater mix, often at the mouth of a river where it meets the sea. 

The range of white-bellied sea eagles extends to Australia’s neighbouring countries of New Guinea and Indonesia. White-bellied sea eagles are also found in China, south-east Asia and India.

White-bellied sea eagles are solitary or live in permanent breeding pairs with established territories.

What do white-bellied sea eagles eat?

White-bellied sea eagles are carnivores. Living around waterways, their prey includes fish, freshwater tortoises and sea snakes as well as waterbirds, mammals and reptiles along the shore line. They will also feed on carrion. ‘Carrion’ are dead rotting animals.

Sea eagles are skilled and aggressive hunters with excellent eyesight. When a sea eagle spots its prey, it swoops down and grabs it with their long sharp talons. It flies up to a tree branch to roost and tear into the prey with its strong sharp pointed beak. 

White-bellied sea eagles have been known to aggressively harass other birds carrying prey so that they drop it to be collected by the sea eagles.

How are white-bellied sea eagles adapted to their environment?

When hunting for prey, white-bellied sea eagles use their excellent eyesight to spot their prey from a perch or whilst flying.

White-bellied sea eagles use their strong feet and long sharp curved talons to catch, lift and carry their prey. They usually fly to a perch to eat their prey which they tear apart using the sharp hook at the end of their strong curved beak. Sea eagles eat some smaller prey whilst in flight. 

White-bellied sea eagles have large strong wings for flying. To conserve energy needed for flapping such large wings, sea eagles find and ride thermal updrafts or air currents to circle high in the sky. Thermal updrafts are invisible columns of warm air that rise from the ground. Sea eagles don’t need to flap their wings as they ride a thermal.

How do white-bellied sea eagles reproduce and what is their life-cycle?

White-bellied sea eagles usually breed from May to October. In a tall tree about 30 metres above the ground, sea eagles build a large nest of sticks and driftwood collected from shorelines. They line it with leaves, grass and seaweed for a soft base. If suitable nesting trees aren’t available they’ve been known to build their nest on cliff ledges, telephone poles, rocks or even the ground. 

White-bellied sea eagles sometimes re-use their nest from previous years, adding new materials each year which can result in very large deep nests.

The female usually lays two white eggs which she usually incubates for about 40 days. ‘Incubate’ means to keep the eggs warm. The young stay in the nest growing quickly and are ready to fly after 65 to 85 days. 

When the juvenile sea eagles leave the nest they are mainly brown in colour and don’t yet have their white adult plumage. Once they can fly, the juveniles stay within the territory of their parents for two to three months.

What is the role of white-bellied sea eagles in the environment?

As apex predators, white-bellied sea eagles help maintain and control the populations of prey animals and so help maintain the balance of nature.

What threats do white-bellied sea eagles face and how can we help them?

Under the NSW Biodiversity Conservation Act 2016, the conservation status of white-bellied sea eagles is vulnerable. ‘Vulnerable’ as a status means ‘at high risk of extinction in the medium term’.

Abandonment of nesting sites due to local disturbances caused by human activities is a threat to white-bellied sea eagles. Human activities such as tourism, off-road driving and building development works close to nests can cause the adult eagles to abandon their nest and incubation duties. 

The use of poisons and chemicals within a sea eagle’s habitat, such as poisoning of rodents or use of pesticides on crops, can result in deaths of sea eagles or reduce their breeding abilities. A sea eagle can die of secondary poisoning from eating a carcass poisoned by a chemical. Being at the top of the food chain, concentrations of poisons in animals along the food chain increase at each level resulting in the apex predator having the highest concentrations.

White-breasted sea eagles can become entangled in the nets of fish farms and ocean debris such as old nets and fishing lines. They can also ingest microplastics that are in the stomachs of their prey animals.

Nesting sites for white-bellied sea eagles are reduced by land clearing for coastal development and could be impacted by rising sea levels due to climate change. 

Humans can help protect populations of white-breasted sea eagles by preventing land clearing and providing buffer zones around nesting sites. Land managers such as local councils can provide management plans for local populations of white-bellied sea eagles aimed at minimising their decline. 

In order to help monitor populations of sea eagles, people can log sightings into biodiversity sites and apps such as the Atlas of Living Australia.

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