Ornithologists at the University have joined forces with researchers from the University of Cape Town to come up with a new way of preventing birds from colliding with power lines, which results in a high number of fatalities in Blue Cranes and Ludwig’s Bustards.
12 per cent of the Blue Crane population (the national bird of South Africa) and 30 per cent of the Ludwig’s Bustard population are killed annually due to collisions with power lines, and there is concern that this high mortality rate will ultimately threaten the survival of these already rare and endangered species.
As South Africa’s economy grows, an increasing number of power lines and pylons are being erected between Johannesburg and Cape Town, straight through some of the most important habitats for these species.
Birmingham ornithologists visited South Africa to find out why these birds are particularly prone to crashing into these obstacles. They discovered that cranes and bustards have a field of vision that has evolved so that they can scan the ground as they are flying, looking for areas to forage, roost and for other birds to mate with. However, pitching their heads to look downwards during flight renders them blind in the direction of travel.
Currently the preferred solution to the problem is to hang objects from the cables, but ornithologists at the University say these devices are only effective if the birds always look where they are going. They have suggested that the best solution to reduce these deaths is to divert birds from their flight path using decoys rather than try to warn them that power lines lie ahead.
Professor Graham Martin, an ornithologist from the School of Biosciences, says, ‘This would mean constructing attractive foraging or roosting areas near sites where bird and power line collisions are particularly frequent. The birds would see these, and see other birds, and would then be more likely to land. This solution takes into account the natural behaviour of the birds. It’s a matter of working with the birds and recognising what they can be expected to see rather than putting something up and saying ‘You must look at this’.’
The ornithologists’ recommendations have implications for bird populations globally. Professor Martin continues, ‘Many millions of birds are killed by power lines around the world, and wind turbines are also becoming more and more of a problem for birds. Our recommendation to build foraging areas would tap into the birds’ natural behaviour patterns by diverting them away from these obstacles – this should help to mitigate the number of bird deaths caused in this way.’
See the bird collisions press release