1. Department of Biology, University of New Brunswick, Fredericton, NB E3B 5A3, Canada.
2. Riding Mountain National Park, Wasagaming, MB R0J 1N0, Canada.
3. Canadian Wildlife Service, Environment Canada, Winnipeg, MB R3C 4W2, Canada.
4. Faculty of Environmental Design, University of Calgary, 2500 University Drive NW, Calgary, AB T2N 1N4, Canada.