About Icthyophaga ichthyaetus (Horsfield, 1821)
The grey-headed fish eagle (scientific name: Icthyophaga ichthyaetus, originally published by Horsfield in 1821) is a smallish to medium-sized, quite bulky fish eagle. It has a small bill, a small head on a long neck, a rounded tail, and fairly short legs with unfeathered tarsi and long talons. Its wings are not very long, with wingtips that reach less than halfway down the tail. This species shows sexual dimorphism. Body length ranges from 61 to 75 cm (24 to 30 in). Females are heavier than males, weighing 2.3 to 2.7 kg (5.1 to 6.0 lb) compared to the male average of 1.6 kg (3.5 lb). Tail length measures 23 to 28 cm (9.1 to 11.0 in), tarsus length measures 8.5 to 10 cm (3.3 to 3.9 in), and wingspan ranges from 155 to 170 cm (61 to 67 in). Adult grey-headed fish eagles are grey-brown overall, with a pale grey head and pale iris. The belly and tail are white, and the tail has a broad black subterminal band. The breast and neck are brown; the upper surface of the wings is dark brown with darker black primaries, and the underwing is brown. Juveniles have brown heads and necks, with a greyer tone on the sides of the throat, buff supercilia, and whitish streaks. The rest of the juvenile upperparts are darker brown, edged with grey, and the secondaries and tertials have faint barring. The juvenile tail is marbled black and white, with a broader dark subterminal band and a white tip. The juvenile belly and thighs are white, while the breast and flanks are brown streaked with white. Juveniles have darker irises than adults. As juveniles mature, the subterminal tail band becomes more prominent, the head becomes greyer, and the body loses streaking to become uniformly brown. The grey-headed fish eagle has a wide distribution ranging from 38° N to 6° S, covering India and Southeast Asia, extending to Malaysia, western Indonesia, and the Philippines. It is generally uncommon across its range, and can be rare or restricted to local populations. In India, it occurs in Rajasthan, Uttar Pradesh, Bihar, and Assam. It is uncommon in northern and eastern Sri Lanka, rare and local in Nepal, and uncommon and local in Bangladesh. It is rare and local in southern Thailand, rare in Laos, and scarce from Vietnam, Cambodia, and Malaysia to Sumatra. It is very rare in Java and Sulawesi, with the exception of a small local population, and scarce in Borneo and the Philippines. This species inhabits lowland forest up to an elevation of 1,500 m (4,900 ft). It builds nests close to bodies of water, including slow-moving rivers and streams, lakes, lagoons, reservoirs, marshes, swamps, coastal lagoons, and estuaries. It also regularly uses irrigation tanks in Sri Lanka. The grey-headed fish eagle is a non-migratory, sedentary species that can be solitary or found in pairs. Only juveniles disperse away from breeding areas, presumably to search for mates or new food sources. This eagle spends most of its time perching upright on bare branches over water bodies, and occasionally flies down to catch fish. Its flight appears heavy, with sharp, full wing beats held on fairly flat wings.
