The electrical energy transportation and distribution lines represent a danger for the birds that frequently die due to collision with the cables or electrocution in the supports. Studies conducted in Portugal indicate that the Great Bustard and the Little Bustard are, among the bird species with a high conservation status, the one that suffer most from the impact of these structures. In the case of the Great Bustard, the collision with power lines is identified as one of the main mortality causes of the species.
Project LIFE Estepárias had, among others, the goal of minimizing the impact of medium voltage power lines in the Castro Verde Special Protection Area (SPA). This SPA comprehends the most important region for the conservation of steppe birds in Portugal, therefore being urgent to implement correction measures to the power lines.
During the course of project LIFE Estepárias, the League for the Protection of Nature (LPN) worked together with EDP-Distribution in applying anti-collision and anti-electrocution measures in 40km of power lines. With the achievement of this goal, the Castro Verde SPA is currently the area of Rede Natura 2000 with the largest extension of corrected power lines in the country.
The selection of the lines considered as urgent for correction was based upon previous studies and the examination carried out by LPN in the areas where Great Bustard, Little Bustard or Lesser Kestrel mortality was recorded, and also considering occurrence data of the species and of more sensitive areas.
The measures applied to minimize the danger of electrocution of birds were the covering of supports of the power lines through the application of cable looms and coatings and by converting horizontal conductors into the vertical position. In what concerns collision preventive measures, the conductor cables were signalized using different types of devices that increase its visibility.
While the anti-electrocution measures had already shown positive results in previous studies, the anti-collision measures applied until now have revealed weak results, not reaching the goal of achieving a significant decrease on the mortality of sensitive species on the signalized power lines. Thus, in the scope of project LIFE Estepárias, a study was conducted in order to determine the effectiveness of three new devices recently made available on the market: the Bird Flight Diverters of the double spiral type, the Firefly Bird Flappers of the flags type and the Firefly Bird Flappers of the rotating type.
We conducted the fortnightly monitoring of around 20km of power lines during three consecutive years. The field work consisted on the prospection of dead birds under the power line, conducted by two experienced observers, with a posterior identification of the birds’ species and cause of death. The results of this study indicate that the Firefly Bird Flappers of the rotating type are the most effective devices in what concerns mortality decrease both of birds in general and of Great Bustard and Little Bustard in particular. In the future, the implementation of measures to prevent collision against existing power lines in steppe habitat areas must include the application of these devices.
However, we cannot say that a type of device is 100% effective in decreasing mortality and, therefore, in case of the installation of new power lines studies must be conducted in order to avoid its installation in sensitive areas for steppe birds and for other threatened birds.
Project LIFE Estepárias was a great example of cooperation between a NGO and a private company with the purpose of finding solutions that can guarantee the protection of biodiversity, and we hope that this type of partnership can multiply in the future to assure the protection of our natural heritage.