African Fish-Eagle

African Fish-Eagle, Icthyophaga vocifer is a species of eagle in the Buteoninae subfamily and the Milvini tribe. It is closely related to the Madagascan Fish-Eagle (I. vociferoides), White-bellied Sea-Eagle (I. leucogaster) and Sanford's Sea-Eagle (I. sanfordi). It is found in Africa, south of the Sahara.

Icthyophaga is derived from Greek, ιχθυοφαγος ikhthuophagos fish-eating  < ιχθυς ikhthus, ιχθυος ikhthuos  fish; -φαγος -phagos  -eating  < φαγειν phagein  to eat; vocifer is derived from Latin vociferari  to cry aloud  < vox, vocis  voice, cry, sound; -fera  carrying  < ferre  to bear.

Description
Length is 63 –; males weigh 1985 –, females weigh 3200 –; the wingspan is 175 –.

Behaviour
Perches for 85–95% of day in productive tropical habitat. Most often seen singly or in pairs on high branches along water. Usually solitary, but more than 100 may gather at concentrations of stranded fish. Hunts mainly from a perch by swooping down to pluck prey from near the water surface, rowing larger prey to shore. Rarely hunts when soaring, but regularly pursues and pirates other piscivorous birds.

Diet
It is a specialised fish eater; more often seen watching from a perch than hunting in flight, it swoops to snatch fish just under the surface, using a backward swing of its feet. It eats fish that are 200 - 1000 g, but also up to 4200 g. It pursues and pirates other piscivorous birds.

It also feeds upon carrion, waterbirds (including colonial species), mammals (monkeys and hyraxes), reptiles (monitor lizards, terrapins and crocodile hatchlings), frogs and even insects; whatever is locally available. Immature birds feed on the kills of Lions and Leopards in Uganda. At Lake Naivasha in Kenya, Red-knobbed Coots and fish were important prey.

Calls
During its display call, it throws its head backwards and forwards. The call is a distinctive, far-ranging “WEEE-AH kleeuw kleeuw kleew” given by both sexes; the loud yelping calls are uttered when perched or in flight, often as a pair in duet, synonymous with the African waterways.

Reproduction
They lay eggs in any month in most regions, but locally seasonal and generally favours low water conditions, with peak in Oct–Dec/Jan in W Africa; Jul–Oct in Uganda; Jun–Aug in S Africa.

It builds large stick nest in high fork of tree as close to the water as possible, rarely on a cliff or a steep slope. Their nests are 120 – across and 20 – deep when first built. Usually lays two eggs (or one-four); incubation is 42-45 days.

Chicks have white down; fledging is 65–75 days; occasionally three young fledge, but often only one-two chicks survive to independence, they fledge in about two months after hatching.