1. Division of Evolution, Ecology & Genetics Research School of Biology The Australian National University Daley Road Canberra ACT 0200 Australia
2. Department of Animal Ecology Netherlands Institute of Ecology (NIOO‐KNAW) Droevendaalsesteeg 10 6708 PB Wageningen The Netherlands
3. British Trust for Ornithology The Nunnery, Thetford Norfolk IP24 2PU UK