Electrocution of Kenya's Birds of Prey
How raptors get electrocuted
A bird lands with its feet in front and wings outstretched. The legs are spindly things, no thicker than match sticks on smaller birds and about the thickness of a pencil on medium to large raptors. The wings are covered in plastic-like insulating keratin feathers. If dry these long flight feather tips can brush against a live wire and not arc the electricity through the body. But if the fleshy part of the wing touches the electricity, it will instantly travel down the arm into the core of the body and across the leg to the foot. The chances increase with the amount of humidity. The thin leg acts like a 5 Amp fuse, the much thicker wing acts like a 30 Amp fuse. The reason so many birds initially survive electrocution is that the 5 Amp fuse “blows” first. It may not kill the bird…but it certainly kills the foot. And raptors use their feet, especially talons, to get food.
Sudden surge in electrocutions
To understand how it happens we need to look at the normal three phase power we have crisscrossing towns, cities and the countryside in Kenya, running right through the heart of conservancies and protected areas. The new concrete poles have multiple reinforcing rods running from top to bottom. Some 10-15% have broken tops with bare exposed rods. After a rain the damp cement becomes ferrous with rust reaching the surface. Even if the cap is thick, cement itself is quite a good conductor of electricity especially when damp. Dry wood is not such a good conductor and that is why we have seen a sudden surge in electrocuted raptors, because plantation-grown wooden posts are being phased out and replaced by concrete posts.
Not only the poles but the wooden cross arms, again poor conductors, are also being replaced by metal. And to compound the danger all the more the insulators are now much shorter, bringing that air gap between live wire and earth so close that in many poles it will electrocute even small songbirds. The wires are naked too, when previously, especially near urban areas, many lines were insulated with plastic. A short circuit can of course also occur from one line to the other, and open wings of even fairly small raptors can span that gap and kill them. So it is that we see a rapid increase in electrocution cases.
Alternatives can be economically viable
Short circuits often cut the power to the user, and while there are automatic trip switches that can turn it back on, there are many times it cannot. This means a power outage and a measurable economic loss and customer inconvenience. This is something we can use to support the return to much safer alternatives or even totally safe options of which there are many.
Treatment of electrocuted birds
Birds are brought to us by people who find them on the ground sometimes near to poles but as often nowhere near to poles. They can fly hundreds, even thousands of kilometers away before their wounds overcome them. Burn marks and the smell of burnt hair (feathers) is typical. Often one leg is slightly discoloured and the opposing wing tip has a bruise on the inside of the carpal (hand). That is all. Even the foot and wing work, but not very well.
Over the next few weeks the limbs atrophy, turn black and die. The trick is to define where the electricity traveled, and do what one can for the underlying tissue. These areas are then treated for burns and swathed in gel gauze. The bird is put on an aggressive course of antibiotics and the limbs are gently massaged to increase blood flow. Often the outcome is disappointing and the limb will need to be amputated and the bird can't return to the wild.
Augur Buzzard with amputated leg and wing.
Tawny Eagle with fried feathers and bad eye.
Martial eagle with amputated wing.