Crowned Eagle Kroonarend “ Stephanoaetus coronatus “

A large crested eagle, the female is considerably larger than the male.

The short black occipital crest, tipped white at the back of the head, is not often seen held upright. The adult is dark grey above and reddish-brown (rufous) below. The breast and belly are heavily mottled with black. In flight, it has well-rounded wings and a long tail, boldly barred black and white. Its wingspan is 1.5 to 1.7 m.

The underwing coverts are rufous ,with the primaries and secondaries white and heavily barred with black. The breast and neck are suffused rufous. The sexes are similar. The sides of the face and neck are rufous to dark brown, and the upper tail grey-brown, with broad black bands. The lesser underwing coverts are chestnut, with greater coverts black and white. The undersides of the flight feathers are whitish, with three narrow black bars and a broad black terminal band. The throat is rufous brown, and the remainder of the underparts are creamy white, heavily and evenly barred black. Its fully rufous feathered legs are finely barred black, and the feet pale yellow. The bill is black, the cere dark grey, the gape is yellow and the eyes are pale yellow.

Juveniles are creamy white underneath, and the upper part feathers are dark grey brown. The tail is blackish with pale grey bars, and white leggings with small brown spots. The eyes are yellow-brown and the cere is grey.

In aerial display the male repeatedly gives a shrill “kewee-kewee-kewee”’ call, while the female gives a lower-pitched , mellower “kooi-kooi-kooi” call synchronously.

They are distributed in tropical Africa from Senegal to Ethiopia. In South Africa they are found only in the east, south to about Knysna. It is discontinuously distributed because of a fragmented habitat. It is most common in dense indigenous forests, including riverine gallery and may range far from a forest to hunt. It is a common resident in suitable habitat, but numbers are declining through deforestation. It is also found in Eucalyptus and pine plantations.

It perches for long periods, resting inside the forest canopy. Sometimes it soars high over a territory, manoeuvring agility through thick forest, and usually descending almost vertically to perch.

This very large eagle is probably the strongest eagle in Africa. Because of their choice of forested habitat they are not often seen. The Crowned Eagle is considered to be a bird of thick indigenous forests. Their food consists mainly of mammals, particularly monkeys, but baboons, dassies, mongooses, cats and game birds are also on their menu. It takes most prey on the ground, but it will crash into dense foliage in pursuit of prey.

They hunt from a perch, and drop onto prey passing below. The prey is struck with a downward blow of an open foot. The massive hind claw penetrates the skull, killing instantly. It is attracted to animals caught in snares. Large prey items that cannot be lifted are partly eaten and dismembered on ground, and then cached in trees. It also takes reptiles, mainly monitor lizards, and rarely tortoises. There is record of a human skull found in one nest.

Both sexes build the nest. It is a large platform built with branches up to 1.5 m long and 30 mm thick. The nest cup is copiously lined throughout the breeding period. Nests reach enormous proportions of up to 1.5 x 1.8 m and up to 0.7 m high. Nests are added to annually. Old nests reach 2 to 3 m in diameter and 3 m in height. In South Africa, they breed mainly during September and October. They are monogamous, probably with a long-term pair bond. They are solitary nesters, and the nest is usually placed in the highest major fork of the tallest available smooth-barked tree. Favoured trees include White-stinkwood, Yellowwoods, and Brown-ironwood, as well as alien Eucalyptus and pines. The nest is regularly reused up to 50 years.

The usual clutch of two eggs is laid four days apart. Eggs are elliptical, dull white, often with faint brown streaks or splotches. Incubation period is 50 days by the female. The male only incubates for short periods. The female occasionally brings prey for the incubating male; this behaviour is unique among African eagles. The incubating bird rises and threatens intruders with raised wings, one of few African eagles to strike the observer climbing to the nest.

Eggs hatch at four-day intervals. The second hatched chick invariably succumbs due to starvation. The older chick is dominant when fed. The male provides prey to the female and chicks and the female feeds the young chick up to 40 days, thereafter the chick self-feeds. The male never feeds, even in the absence of the female. The chick moves onto branches near the nest before its first flight, usually 110 to 115 days after hatching. Occasionally two young may survive.

The breeding pair provides prey to the juvenile for up to 10 months after fledging, and then the juvenile is driven out of the territory.

The Crowned Eagle is not globally threatened, but is near-threatened in South Africa due to the loss of forest habitat, the latter partly offset by the establishment of alien plantations.

Albert Froneman

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