1. ENES Bioacoustics Research Team, University of Saint-Etienne, 42100 Saint-Etienne, France
2. Department of Life Sciences and Systems Biology, University of Turin, 10124 Turin, Italy
3. Southern African Foundation for the Conservation of Coastal Birds (SANCCOB), Cape Town 7441, South Africa
4. Department of Biodiversity and Conservation Biology, University of the Western Cape, Robert Sobukwe Road, Bellville 7535, South Africa
5. Statistics in Ecology, Environment and Conservation, Department of Statistical Sciences, University of Cape Town, Rondebosch, Cape Town 7701, South Africa
6. Institute for Coastal and Marine Research, Nelson Mandela Metropolitan University, Port Elisabeth 6031, South Africa
7. Institut Universitaire de France, Ministry of Higher Education, Research and Innovation, 1 rue Descartes, CEDEX 05, 75231 Paris, France
8. CAPE Department, Stazione Zoologica Anton Dohrn, 80121 Naples, Italy