In the Netherlands and internationally, the impact of wind farms on birds is receiving increasing attention. Birds of prey are relatively frequent victims of wind turbine collisions in comparison with other species groups, and their populations vulnerable to the resulting addition mortality. Approaches are needed to mitigate the possible effects of the energy infrastructure, for example: (1) habitat management, to keep foraging birds of prey away from risky turbines, (2) contrasting colors on turbine rotors to prevent collisions, or (3) targeted standstill of turbines when collision risks are highest.
Such mitigation actions are best undertaken in areas where risks are high. However, due to a lack of knowledge about flight behavior in relation to wind turbines, very little is known about mortality risks in time and space. Application of state-of-the-art GPS transmitter techniques in birds for the investigation of avoidance and flight behavior (flight altitude, per season, with varying weather conditions) contributes to the necessary improvement of collision risk assessments and sensitivity analyses, especially for mobile species. Based on this, effective mitigation measures can be deployed in high-risk areas. We investigate in detail the flight behavior and habitat use of eagles, harriers and vultures, both in the Netherlands and in Kenya. Collision risks can be modeled on the basis of detailed information on flight movements of raptors and axis height and location of existing and planned wind turbines. We identify potentially risky areas for spatial planning of energy infrastructure and the use of specific mitigation methods where and when the risks of collisions are highest.