Colours of Wildlife: The Brown Snake Eagle
Created | Updated Mar 4, 2012
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!"
The Brown Snake Eagle
Today's painting is another one that is special for me. I used a photograph I had taken myself. It was of a bird in a rehab centre for raptors, on a stump in a cage. In my painting I set it free!
This is a Brown Snake Eagle, Circaetus cinereus. This species is one I have seen on several occasions in the wild, as it is not at all rare. It occurs in Africa south of the Sahara, in savannah woodland and bush country. It avoids rainforests, open grasslands and deserts.
These eagles can often be seen in flight, soaring, sometimes scanning the ground or even fluttering in place a few metres (or yards) above the ground, looking at a particular spot. Most of the time, however, it will sit on a perch in a tall tree, or in a tree on a small hill (koppie), from where it can watch over a large patch of land. It typically has a very upright posture, as you can see in my painting. It has large, yellow eyes giving it excellent vision and a rather owl-like appearance.
This is one of five (or six, depending on which taxonomist you ask) snake eagle species in Africa belonging to the genus Circaetus. It is easily distinguished from the others by its plain, dark brown plumage. In good light a slight purplish sheen can be seen on its upperparts. It is quite a large eagle, reaching 2.5 kg/5.5 lbs in bodyweight with a wingspan of 2 m/6'7". It has a compact body and short tail, with short but sturdy legs and feet. Unlike some other large eagles its legs are unfeathered, covered with tough scales to protect it against snake bites.
And when it comes to snakes, it is quite an expert, much like the Secretary Bird , though its techniques are very different. It will grasp the snake with its strong feet and peck at its head, neck and back, trying to break its spine. Incredibly, this eagle frequently deals with the most feared snakes on the continent, such as the Puff Adder, the Black Mamba, the Boomslang, and several species of Cobra. It was once seen to kill a Black Mamba that was a tad over 2.7 m/9 ft in length! This is a snake that is said to move faster than any other in the world. Popular tales speak of it keeping pace with a galloping horse – but this is in fact exaggeration; nevertheless, the black mamba could perhaps attain a speed of 20 km/h/about 12 mph. And its strike speed is equally fast – the Puff Adder's may be even faster. And yet, this bird deals with these snakes as a matter of routine.
Sometimes its prey does get the better of it. One ornithologist came upon a Brown Snake Eagle that had a Mole Snake (a large but nonvenomous species) in its grasp – but the non-grasped part of the snake had coiled itself around the eagle, and neither seemed willing to let go. The ornithologist freed the eagle, but if this intervention hadn't happened, both the snake and the eagle might have died.
Perhaps the most 'amusing' (for want of a better word) aspect of this eagle's behaviour involves the feeding of these snakes to its chicks. Initially the female will brood and shade the chick (there is typically only one) while the male would bring it meals. These consist of entire snakes, which the male swallows head first but leaving a bit of tail hanging out of his mouth. Then when he lands, he will either try to hook it out with his foot, or the female will grasp the tail in her bill and then pull it out, while the male strains backwards. Then when it's out, she will bite it into smaller bits for the chick to swallow.
After about the third week, the female will also start hunting snakes for the chick, leaving it unattended for most of the day. The nest is typically smallish, and right on top of a dense-crowned tree like an Umbrella Thorn or a Tree Euphorbia. It is situated so as to be practically invisible from below, and the chick will, when unattended, lie quite flat and remain quiet so as to be inconspicuous. But when it sees one of its parents approaching, it will start calling excitedly. When the parent lands, the eaglet goes into a hunched posture and makes a soft squealing noise. Then the parent will hold the bit of snake tail sticking out towards the chick, which will grasp it and pull it out itself. By the age of five or six weeks the chick will be able to swallow a metre-(or yard-) long snake in one piece, including large Puff Adders (which are not very long, but the fattest of all venomous snakes). To get this sort of thing down its throat it goes through a series of violent jerks and contortions, and the swallowing rate is typically 30 cm/1 ft a minute.
Sometimes when the chick is young the parent will eat the head of the snake first before letting the chick have the rest of it. But it seems as if the chick (not to mention the adults) can in fact swallow and digest snakes with fangs and venom glands and all without any problems.
They don't eat only big poisonous snakes, though … often the prey would be somewhat smaller and/or nonvenomous species like grass snakes or blind snakes. It will sometimes catch other reptiles like monitor- and other lizards or chameleons. In Kenya it has also been seen to catch toads, rats, and other birds – especially wild partridges. But these kind of prey items have not yet been recorded for it here in South Africa.
Overall, this species is probably not in any immediate danger. Since it eats mostly snakes it can actually be considered a rather useful raptor species, and not in much danger from eating poisoned carcasses (which is a bane of many larger eagle and vulture species). However, it is at risk from ongoing habitat loss – as is pretty much every wild thing on this planet with the way we humans are carrying on.
