1. Department of Evolution, Ecology & Genetics Research School of Biology The Australian National University Canberra ACT 0200 Australia
2. Department of Animal Ecology Netherlands Institute of Ecology (NIOO‐KNAW) Droevendaalsesteeg 10 6708PB Wageningen The Netherlands
3. Centre for Avian Population Studies Nijmegen the Netherlands
4. Department of Animal Ecology and Physiology Radboud University Heyendaalseweg 135 6525 AJ Nijmegen The Netherlands