A research team led by the Museum für Naturkunde presents the first evidence that several bat species produce courtship songs in the immediate rotor-swept zone of wind turbines while circling around the nacelle. Data from over 80,000 audio recordings at nacelle height from six German sites, together with stereo-thermal 3D reconstructions of bat flight trajectories, document both bat song and elevated bat density in the rotor-swept zone. Both lines of evidence suggest that, under certain circumstances, bats actively approach wind turbines and provide an explanation for why collision risk may increase during the mating season.