1. Atlantic Laboratory for Avian Research, University of New Brunswick, P.O. Box 4400, Fredericton, New Brunswick, E3B 5A3, Canada
2. National Audubon Society Seabird Institute, 12 Audubon Road, Bremen, Maine 04551, USA
3. Atlantic Laboratory for Avian Research, University of New Brunswick, P.O. Box 5050, Saint John, New Brunswick, E2L 4L5, Canada