The call of Africa
African Fish-Eagle – Haliaeetus vocifer (Afrikaans: Visarend)
The African Fish-Eagle is probably the best known and the most striking of the African birds of prey. It has what can be called the Call of Africa, a plaintiff yelp, made with the head thrown right back over its shoulder whether in flight or perched on a branch.
The male and female are similar, with a white head and breast, chestnut belly, black wings and a short white tail. The legs are bare. The talons are long and very strong, with padding for gripping slippery fish in flight as the bird skims over water.
The preferred prey of the Fish-Eagle is live fish, but when this is not available they will take carrion, dead fish, water birds such as flamingoes and herons, and young birds on their nests. They are also great at robbing other birds that are busy eating, such as herons, cormorants and hamerkops. The fish-eagle does not dive into the water like kingfishers or cormorants, but snatches fish that swim near the surface. These include mullet, carp and black bass.
The Fish-Eagle will whenever possible fish in fresh water in lakes, estuaries, rivers and dams, but birds that live on the coast may at times also fish in the sea.
Fish-Eagles build huge stick nests for breeding, either on a cliff ledge or in a tall tree. Two or three eggs are laid and as a rule all the chicks will survive, as they do not seem to have the Cain-and-Abel syndrome of other large eagles. The female does all the incubating, with the male supplying the food. When the chicks are bigger and the female needs to go off to hunt as well, the male may stay with the chicks on the nest until she gets back.
At Potberg (now in De Hoop Nature Reserve) on the coast near Bredasdorp the Fish-Eagle nest was on a ledge on a very high cliff. There was a cave of about 6 metres deep and 1,5 metres wide and high which was perfect for putting our hide in, but we had to go down a 20 metre rope ladder to get to it!
The farmer told us that every night a troop of baboons came to sleep on the same ledge, but in the three years that the eagles had been there, the baboons had left them strictly alone. This was hard to believe, but we soon saw it for ourselves. The two chicks both fledged successfully, as had been the case for three years.
The eagles brought in mainly fresh-water fish, caught in the two dams on the farm or in De Hoop Vlei, but occasionally they brought sea fish, mainly mullet and sometimes yellow-tail. They then invariably flew to where a small stream from the cliffs formed a pool before entering the sea. They dived into the fresh water and splashed around a bit to get rid of the salt on their feathers, and would then perch on a log nearby to dry their feathers.
There was another nest about 2 km away that was simply placed on a little peninsula that anybody or any predator could just walk onto. That also survived.
At Faure on the Eerste River, Klavervlei with a water area of 23 hectares had plenty of fish – bass and Tilapia capensis – but the vlei was covered with waterblommetjies (Cape Hawthorn). For about nine months of the year the willow trees on the islands were exposed, but the fish weren’t available to the one or two young Fish-Eagles that came every year from Paardevlei, the reclaiming dam at the explosives factory nearby. They made use of the next best prey – coot, of which there were always about 50 breeding pairs. The young birds would fly over the vlei, the coot would all cluster together in what is known as a “raft” and the eagles could take their pick: for the first two months of their lives they lived on coot. They would then go to other farm dams in the district to practice their fishing skills. This went on for a number of years, until the explosives-and-chemical factory closed down.
An interesting cycle occurred at the salt pan at Vermont near Hermanus over the past couple of years. Fish-Eagles used to frequent the pan, but left two years ago when a fungus became established in the pan, destroying the oxygen in the water and killing the fish and other water creatures. The water has now become clear again and the fish are back, although not in large numbers yet. The cry of the Fish-Eagle can once again be heard. We are hoping all will be well and the Fish-Eagles may once again breed in one of the tall Eucalyptus trees growing on the northern side of the pan.
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