1. Cognitive and Cultural Ecology Research Group, Max Planck Institute of Animal Behavior, Am Obstberg 1, 78315, Radolfzell, Germany
2. Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Konstanz, Germany
3. Edward Grey Institute, Department of Zoology, University of Oxford, South Parks Road, OX1 3SZ Oxford, UK
4. Department of Evolutionary Biology and Environmental Science, University of Zurich, Zurich, Switzerland
5. Department of Collective Behavior, Max Planck Institute of Animal Behavior, Universitätstrasse 10, 78464 Konstanz, Germany