Collision prevention systems in power lines: birdwatching

Overhead power lines for transporting energy are a more than common element anywhere in the world. Their designs and sizes are as varied as the landscapes where we can observe them. Although they all have in common the type of impacts they generate on fauna, especially on the bird group. Thus, two basic types can be defined: mortality due to collision and mortality due to electrocution.

Although in older lines we usually find both types, since the appearance in Spain of specific regulatory regulations in design (e.g. Decree 5/1999 from Castilla-La Mancha or the Royal Decree 1432/2008 at the national level), electrocution incidents in the new facilities have practically disappeared. This is because construction requirements require minimum distances between structures to avoid contact of birds with electrically conductive parts. However, state legislation seems to have relegated collision conditions to the background by not establishing minimum guidelines for action and leaving it to the Autonomous Communities to decide to install systems that mitigate them. And although these types of regulations have been key in reducing the overall impact, they have not prevented collision mortality from continuing to act wherever a new power line is built.

Currently, one of the most common options for reducing collisions is the placement of bird savers. Los Bird saver they are physical elements that are installed in conductive or ground cables and that increase their visibility by increasing the profile of the cable by playing with shapes and materials. Although it is a measure whose effectiveness varies according to studies, models and species, there is a consensus that its use reduces mortality due to collision, and that this can become very relevant in certain species and situations. In other words, it's a solution that works.

The market is full of different designs applicable to the different tensions and regulations of the countries. In Spain, the most used are spirals And the neoprene straps, and sometimes also the clamps. However, some of the latest studies that have tested the effectiveness of different models suggest that swinging bird savers are more effective. In our country, their use has been scarce and relatively recent, and they are currently being applied, as far as we know, in lines of REE and in some infrastructures in Castilla-La Mancha. Although we hope that little by little its use will become more widespread.

On the other hand, it is our obligation to remember that bird savers are not a panacea and that they will never replace proper planning or good prior study. Your application should be a final tool when there is no better and more effective option. And this is the case because, despite their effectiveness, the sparrowhawks do not reduce the collision to zero and there will always be species and specimens affected in degrees that may not be acceptable for conservation.

Finally, we would like to leave you with some technical information related to birds, collisions and bird savers. By clicking on the titles you can access the full document or, failing that, your editorial review. We hope you find it useful.

• Corona Testing Devices Used to Mitigate Bird Collisions. California Energy Commission.
• Evaluating Diverter Effectiveness in Reducing Avian Collision with Distribution Lines at San Luis National Wildlife Refuge Complex. California Energy Commission.
• Meta-analysis of the effectiveness of marked wire in reducing avian collisions with power lines. Conservation Biology 25:893—903.
• Suggested Practices for Avian Protection on Power Lines: The State of the Art in 2006. Avian Power Line Interaction Committee (APLIC).
• Understanding bird collisions with man-made objects: a sensory ecology approach. Ibis 153 (2): 239—254.
• Visual fields, foraging and collision vulnerability in Gyps Vultures. Ibis 154 (3): 626-631.
• Wire marking results in a small but significant reduction in avian mortality at Power Lines: A BACI designed study. PLoS ONE 7 (3): e32569.