1. Natural Resources Institute, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
2. Department of Biological Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
3. Lab of Ornithology, Cornell University, Ithaca, NY 14850, USA
4. Environment and Climate Change Canada, QC J8X 4C6, Canada
5. School of Biological Sciences, University of Aberdeen, AB24 3FX Scotland, UK