Parental role division predicts avian preen wax cycles

1 Royal Netherlands Institute for Sea Research (NIOZ), PO Box 59, 1790 AB Den Burg, Texel, The Netherlands 2 EECB Program/MS 314, University of Nevada, Reno, NV 89557, USA 3 Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, BC V5H 1S6, Vancouver, Canada 4 Haerdewei 62, 8854 AC Oosterbierum, The Netherlands 5 U.S. Fish and Wildlife Service, Migratory Bird Management, 1011 E. Tudor Road, MS 201, Anchorage, AK 99503, USA 6 Canadian Wildlife Service National Wildlife Research Centre, 100 Gamelin Boulevard, Hull, Quebec, Canada K1A 0H3 7 University of Alaska, Department of Biology and Wildlife, Fairbanks, AK 99775 USA 8 Alterra, PO Box 167, 1790 AB Den Burg, The Netherlands 9 Zoological Museum, Moscow State University, Bolshaya Nikitskaya Street 6, 125009 Moscow, Russia 10 Animal Ecology Group, Centre for Ecological and Evolutionary Studies, University of Groningen, PO Box 14, 9750 AA Haren, The Netherlands