A Five-Year Spanish Research Project on Bird Electrocution and Collision with Electric Lines

Jorge Roig-Solés and Víctor Navazo-López

The project, which could be considered unique world-wide for its scope and magnitude, was carried out in different environments of natural protected areas in Spain during a period of five years (1991–1995). The project objectives were to evaluate bird accidents at powerlines, to identify the causal factors and to develop protection measures. In order to establish the extent of the problem and to see which technical factors were involved, 21,000 structures and 520 power line spans were surveyed and one thousand hectares were monitored. Also one thousand hours of video film were dedicated to the observation of birds perching on electric structures, which were equipped with experimental devices to prevent electrocution. Besides the size of the bird, the frequency of electrocutions depends on the habitat and the design of tower. Birds being more prone to electrocution are those that most frequently perch on high vantage points. The mortality for collision, however, depends on the characteristics of the bird species. Some species are not very prone to collision, and others much more so. The efficiency of different protection systems is discussed, as well as the definition of the optimal policy for the construction of new lines and for the protection of the existing ones. Promoters of the project were the electric utility companies Sevillana, Iberdrola and Red Eléctrica, supported by different environmental agencies. The research was planned and carried out by the Spanish Superior Council of Scientific Research.

Keywords: Birds, electrocution, collision, powerlines, protection measures, mortality