By Jerome Kannemeyer
The title begs the question of who is the best fishermen alive?
This topic is a rather contentious one, particularly when the fishing is done and the rivalry over the days catch ensues, but today we are not referring to a person, not even a human – but the African Fish Eagle (Haliaeetus vocifer).
These beautiful birds are one of the most impressive birds occurring in Sub Saharan Africa. They are easily recognized by their distinct call which can be heard resonating from large nearby rivers, lagoons, lakes and estuaries, sometimes referred to as the call of Africa.
African Fish Eagles are often seen perching on trees overlooking the waters, with their white head, breast and tail, in contrast with their chestnut and black wings, back and under-parts. Females, being larger the than males, have a more extensive white breast in comparison. Males weigh from 2 to 2.5 kg, while females weigh around 3.2 to 3.6 kg.
African Fish Eagles swoop down to catch their meal and take it back to their perching site. They spend around more than 10 minutes a day looking for food. If the prey is too heavy (exceeding 1.8 kg) though, they are known to drag it to shore over the water. This eagle species preys not only on fish, but also the young of water birds such as lesser flamingos. It has also been noted that they prey on monkeys, crocodile hatchlings, frogs and insects. They also steal food from other birds like storks, pelicans and other water birds. In time of food scarcity, African Fish Eagles have also been known to scavenge, feeding on carcasses much like a vulture.
African Fish Eagles do play an important role and are recognized as a bio-indicator species, meaning the presence of some animals can be good or bad but in this case the fish eagle being good.
If rivers, lagoons, lakes and estuaries that should naturally harbor these birds, lack their presence, this suggests there is something wrong with the system. As fish are a primary prey for the African Fish Eagle, a system without the eagles may suggest that the prey source in deficient. A lack of fish may mean that there is something in the system that keeps the fish away or that the stocks have been depleted, therefore not making it worthwhile for the African Fish Eagle to live in the area. On the Breede River, we occasionally sight these birds as it is an indicator of the health of our river and knowing that we look after our fish .The ecosystem is therefore maintained by a delicate balance of prey and predator and the actions of one are determinant of the other.
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Available at: https://www.arkive.org/african-fish-eagle/haliaeetus-vocifer/
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BBC Nature UK, 2014. Nature Wildlife – African Fish Eagle. [Online]
Available at: https://www.bbc.co.uk/nature/life/African_Fish_Eagle
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Grennouillet, M.F., 2015, African Fish Eagle [Photograph] (Wildlife Capture; Zimbabwe – Raptors)
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