Detection-reaction systems in onshore windfarms, a mitigation solution to reduce bird fatalities: Principles for a relevant assessment of their performances

In onshore wind farms in operation, avian mortalities are observed, especially on patrimonial species. The regulatory need for the operators of these farms to reduce these mortalities, passes by the installation of various means of reduction. One of these means is the detection-reaction systems which allow to detect the target bird’s species and to react (scaring or flanging of wind turbines) before the collision. These systems are becoming more and more developed on the world market, with evaluations made from all sides. In this paper, we describe the functioning of the different technologies of these systems and propose a good way to evaluate them considering the different influencing factors and in a perspective of statistical reliability. These guidelines will serve as a reference for the different actors who order, implement, or evaluate the tests of these detection-reaction systems.