The catchment area of wind farms for European bats: A plea for international regulations

► European windfarms kill large numbers of bats at night. ► We used hydrogen stable isotopes to model the provenance of these bats. ► German windfarms kill bats from both local and distant populations. ► National regulations for establishing windfarms do not take this into account. ► Measures are urgently needed to mitigate the large-scale negative effects on bats.