Electricity distributors worldwide have had to look at and design ways to minimalize the impact of birds’ flight, perching and nesting on the structures of an electricity network. Birds can cause problems for electricity distributors and their customers when they collide with power-lines or conductors, contaminate insulators and other equipment with nesting material or excrement causing flashovers that can lead to damage or disruption of power. All disruptions are at great expense to consumers, especially industrial consumers and of course the actual utility in our case Nampower, must find and fix the problem.
Besides the obvious costs to suppliers and consumers through power outages there is yet another more insidious cost to all of us. This cost to biodiversity through electrocution of birds, those that are resident and those that migrate to Namibia for the summer can be quite significant. For example in countries where data has been collected, up to 43% of fledged immature eagles have been killed by power grid accidents. In Namibia where we have far lees density of overhead structures the numbers should be much lower, however we do not have data and there is a current thrust in the development of the electrification network throughout the country.
Even discounting humane reasons for improving old structures and developing safer hardware designs there is also the fact that throughout the world the birds that are mostly impacted are endangered species and these populations cannot afford powerline casualties. One group of birds that tend to both have and cause problems on the grid are birds of prey. The reasons that they use the overhead structures are because high structures increase their range of vision for hunting, increase their attack speed when they perch-hunt, make excellent roosting platforms from where they easily defend and broadcast their territories and for some the pylons make perfect spaces for nest building.
Large birds’ have wingspans of up to 2.8 meters making the distance between conductors and conductors to ground one of the main causes of electrocution for birds landing on structures. Young birds may be more susceptible than adults because they lack flight control and are sometimes quite unsteady when landing. Species such as ducks and bustards fly at low altitudes with incredible speeds. These heavy bodied birds lack flight agility and they often become victims of power cable collisions. Other birds such as flamingoes that fly at night are simply unable to see the cables if the are flying at low altitudes.
Together with future planning of range extensions to the electricity network, Nampower is currently embarking on an environmental safety project. The project, supported by the Namibia Nature Foundation (NNF) has as their mission to develop a multi-disciplinary mechanism to assist Nampower in the management of impacts on the natural environment. A first step is to collect and collate information on all impacts of the electric networks’ hardware on Namibian biodiversity and vice versa. Namibia is far from being a pioneer in this field. The very first recorded warning about birds and the overhead electricity network was given in 1913 albeit in Europe. In southern Africa, the Endangered Wildlife Trust (EWT) together with ESKOM, the South African electricity network supplier, has had decades of investigation into the bird/power line issue.
One of the aims of the Nampower/NNF project is to monitor and investigate accidents on power-lines. NARREC (Namibia Animal rehabilitation Research and Education Centre) has received two power-line victims in the past month, both large birds of prey. Electric burns can be most severe and the Black-chested Snake-Eagle was humanely euthanized. However the Martial Eagle, Namibia’s largest eagle species, with extensive burns to her left wing was lucky enough to be found by Mr. Richard Peterson, a concerned member of the public. This bird arrived at NARREC with severe infection of the wound and a weight loss of about 30%, which reasonably could mean that she had been on the ground wounded for about a week. Just four weeks later and already at a weight of 4.8 kg, she is out of NARREC’s intensive care facility and in a rehabilitation aviary as she is prepared for release.
Martial Eagles are a highly endangered species in Namibia, a 3-fold decrease in the Martial Eagle population has been noted in just 6 years, and they are vulnerable to becoming “endangered status” throughout southern Africa. The threats to these eagles’ future survival are mostly from small livestock farmers who view them as a predation threat to lambs. However, although they obviously are able to predate on lambs they are also a natural predator for jackal, fox, caracal, African wildcat and large reptiles such as cobras and seed-eating birds such as guinea-fowl.
The current Nampower-NNF project will hopefully be able to gather sufficient data to be able to understand the effects of the electricity network locally on all affected species. Nampower will also be able to apply recommended adjustments to electric-grid hardware in order to avoid both death and injury to wildlife and expensive power outages to consumers.