Abstract
To reduce climate-damaging CO₂ emissions , wind turbines have been increasingly erected in recent decades. It has become apparent that birds of prey, especially red kites, are threatened by collisions with wind turbines. Our findings aim to contribute to a sustainable reduction in the collision risk for red kites. To this end, we investigated the flight activity and altitude of 37 GPS-tagged red kites in various natural habitats throughout Hesse. More than 582,800 location data points over 127 individual-years were analyzed over a seven-year period, taking into account wind speeds and land use – specifically, open land, forest, and anthropogenic structures. Flight altitudes varied considerably between individuals and land-use types, with approximately 62% of all flights occurring over open land. More than a quarter of the flight movements took place within the altitude range swept by the rotor blades of current wind turbines. Future turbines, by shifting the rotor area to greater heights, will likely lead to a decrease in this proportion. Furthermore, consistently high flight activity was observed across the entire range of wind speeds. We see a promising approach to reducing the collision risk in increasing the cut-in wind speeds for wind turbines. Activating them at average wind speeds of at least 7.4 m/s over open land and 7.6 m/s over forest would eliminate 90% of all flight movements from the collision risk with rotating rotors whose blade bases exceed 80 m above ground level. Submitted on April 18, 2024, accepted on July 21, 2024.