The white-bellied sea eagle (Haliaeetus leucogaster) is the largest raptor in Bako National Park and one of the most visible. A resident breeding pair nests on the sandstone cliff face near the southern headland of the Muara Tebas peninsula, and both adults can be seen patrolling the park's coastline from dawn to mid-morning on most days. With a wingspan of up to 220 cm and a distinctive white head, breast, and underwing contrasting sharply with dark grey upperparts, it is unmistakable in flight.
Sea eagles hunt from the air, dropping on fish near the surface, grabbing sea snakes, and occasionally taking waterfowl or small mammals from the shoreline. At Bako, the broad bay at Telok Assam is a regular hunting ground — watch from the beach or jetty in the early morning for a diving strike. The eagles also steal catches from brahminy kites and osprey in a behaviour called kleptoparasitism, harassing the smaller bird until it drops its prey and catching the fish before it hits the water.
The resident pair is believed to have nested at the same cliff site for many consecutive years — sea eagles mate for life and are highly site-faithful. The nest is a large platform of sticks and debris wedged into a cliff crevice, inaccessible without climbing equipment. Breeding season in Sarawak is typically October to February, and fledglings — recognisable by their mottled brown plumage — can sometimes be seen accompanying adults on patrol flights from March onward.
The best vantage point for sea eagle observation at Bako is the elevated section of the Bukit Gondol Trail, where the cliff-edge perspective allows you to watch the birds at eye level rather than looking up from the beach. A second reliable viewpoint is the sea cliff overlook on the Lintang Trail near the padang section. Binoculars are essential — the birds patrol at height and may appear as small silhouettes without optical assistance. Mornings after calm nights are consistently the best for aerial raptor activity across the park.