There are two fundamental questions on the interaction of animal species that intrigue me:1) What ‘knowledge’ do animals have of the behaviour and the ecology of other animal species (heterospecific recognition hypothesis)?2) Do differences in sensory ability play a role in mediating resource partitioning between coexisting, potentially competing animal species (sensory niche partitioning hypothesis)?The central aim of the proposed project is to tackle these questions where species interactions really happens: out in the field (years 3-5). The model system will be a European community of bat species. Bats are an ideal model system, because they largely live in an acoustic world. Echolocation calls of heterospecific bats and acoustic prey cues can be experimentally manipulated and presented in field playback experiments.The central commitment of this project is to study animal behaviour using an experimental and hypothesis driven approach.To reconcile aim and commitment, I want to develop (year 1-2) automated experimental stations (AES) that can be deployed in the field. These stations will autonomously interact with wild animals, run individualized experiments and gather high-quality data for hypothesis testing. A key element will be a loudspeaker array that for the first time can realistically simulate moving sound sources (echolocating bats or prey insects) in the field. The proposal thus strives to answer ecological and evolutionary questions at a new level by developing and employing new technical apparatus, which will remain available for future applications beyond this project.The project will be hosted by the Max Planck Institute for Ornithology in Seewiesen, Germany, where I will benefit from a world-class, stimulating research environment. Field work will be conducted in Bulgaria in cooperation with Bulgarian colleagues and students.