Light pollution is rapidly increasing around the world. Nocturnal animals are likely to be especially affected, but how they respond to artificial light is still largely unknown. In a new study, scientists from the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW) in Berlin, Germany, tested the response of European bats to red and white light sources during their seasonal migration. Soprano pipistrelles (Pipistrellus pygmaeus) and, to a lesser degree, Nathusius’ pipistrelles (Pipistrellus nathusii) were recorded more frequently near red LED light, indicating that the animals might be attracted to red light during their migration. In contrast, the scientists did not observe such behaviour near white LED lights. The wavelength of the experimental red LED lights was similar to that of red safety lights used for indicating the presence of wind turbines or tall buildings to aircraft pilots. Warning lights such as these might therefore lure migrating bats toward the very danger they help people to avoid. Switching to more bat-friendly lights or deploying on-demand lighting that only activates if an airplane approaches would most likely reduce bat collisions and bat casualties at wind power stations. The study has just been published in the scientific journal Ecology and Evolution.