Willem is a wildlife artist based in South Africa. He says "My aim is simply to express the beauty and wonder that is in Nature, and to heighten people's appreciation of plants, animals and the wilderness. Not everything I paint is African! Though I've never been there, I'm also fascinated by Asia and I've done paintings of Asian rhinos and birds as well. I may in future do some of European, Australian and American species too. I'm fascinated by wild things from all over the world! I mainly paint in watercolours. . . but actually many media including 'digital' paintings with the computer!"

We look at birds again, and a most impressive species this time. It's Verreaux's Eagle, Aquila verreauxii. It was named for French naturalist Jules Verreaux (pronounced 'vero'), who visited southern Africa in the Nineteenth Century and collected the type specimen of this eagle species for the French Academy of Sciences. It is also called the Black Eagle, especially in South Africa, but this name might confuse it with other black eagle species occurring elsewhere. In Afrikaans it is called a 'Witkruisarend' (White-rumped Eagle) but the white rump is not always visible. It is striking, though, if the bird is seen from above in flight.

This is one of the most impressive and iconic eagles in Africa. It is among the largest, growing to a length of 96 cm/38" in length from beak to tail, and with a wingspan that can reach 230 cm/7'7". It is lighter than it looks, weighing on average 4.2 kg/9.2 lbs, but some females (the larger sex) reach 7 kg/15.4 lbs. Adult birds are striking jet black, with a contrasting white rump that stretches into an 'Y'-shape over the back and shoulders. There are also pale panels in the wings, lightest towards the wingtips, that can be seen when the birds are in flight. They have yellow feet, 'ceres' (the fleshy skin at the base of the bills), 'eyebrows' and rings around the black eyes. Juveniles are quite different, with plumage a mottling of blacks, browns and whites, a golden crown, and ginger or rufous rump and upper back. They attain full adult plumage over about 5-6 years.

Verreaux's Eagle actually has a very specialized way of life. They are associated with rocky hills and mountains, where they feed almost exclusively on Rock Hyraxes. These conveniently-sized chunks of meat are also targeted by a large number of other predators. An adult eagle couple typically catch and eat one medium-sized hyrax per day between them. You can imagine the heavy toll this takes on hyrax populations, but luckily these strange little ungulates breed rapidly enough that they can make up for the predation. Hyraxes are most often caught by surprise while they bask in the sun; the eagle will swoop rapidly over the hillside, grab the hyrax and quickly kill it with its extremely powerful claws. When hyraxes can't be caught, other small mammals like monkeys, rodents, small carnivores or even small antelopes. They also eat a variety of birds, and even on occasion termites, as do almost everything in Africa when the winged alates are swarming. In spite of farmers' fears, they've only been noted eating domestic lambs on a couple of occasions, often when the lambs had already been dead.

Verreaux's Eagles make extensive use of the updrafts of warm air around the mountain slopes and rock outcrops. These rising columns of air enable the eagles to soar almost effortlessly, hardly needing to flap a wing at all for many hours. They are most often spotted soaring like this. When not, they typically perch conspicuously on a big rock, like in my painting. From here they can both see much of their territory, and be seen by potential intruders.

On the whole, Verreaux's Eagles respect each other's territories, and conflicts are few. Home range size varies from about 10 square km/4 square miles in the productive Matobo Hills of Zimbabwe, to over 65 square km/25 square miles in the Magaliesberg and Drakensberg of South Africa. While adults stick to their territory, juveniles range widely in search of suitable living spaces for themselves. Settled adults use a display flight that includes soaring, tumbling and swaying from side to side. Males and females may soar together, making circles or figures-of-eight over their territories. A very spectacular display is when two birds lock their claws together and tumble precipitously out of the sky, dislodging and swooping up again at the last minute – though one time a pair of eagles doing this landed in the sea! This is also done aggressively between a resident bird and an intruder.

The nests of these eagles are almost always built on cliffs, from sticks and twigs, forming an often huge, bulky structure. The eggs are laid on top of this. The rocks around the nest are streaked white with the eagles' droppings. A behaviour this eagle and some related species are notorious for, is the so-called cainism, where typically two chicks hatch, some days apart, and the elder, stronger chick kills its sibling. This apparently happens always; even on the rare occasions when the older chick doesn't kill the younger, it will dominate the food so that the other one starves to death. But there are very rare occasions where two chicks survived to fledging. Chicks are also sometimes threatened by other predators, and the eagle parents have been seen to drop sticks on them to drive them away! The eagles fledge at the age of 90 to 100 days. For 45 to 50 days, the parents still catch food for the fledgling, but then it is responsible for feeding itself. It still flies with its parents for six months, before seeking its own territory. This allows the adults to breed every year. But only 40%-50% of breeding attempts result in a successfully fledged chick. An eagle that survives to adulthood can expect to live for about 16 years.

Currently, these eagles still occur widely over sub-Saharan Africa wherever there is suitable habitat; they appear to occur rarely in the Middle East from Lebanon to Saudi Arabia. Nevertheless, like any large eagle, they occur few and far between so that their global population numbers only in tens of thousands. Nevertheless, their habitats are fairly secure and they don't suffer much from human activities or persecution. If the wild hills of Africa, and their hyraxes, survive in fairly decent condition, then so should these magnificent eagles.

Willem

15.04.24 Front Page

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