1. Environment Canada; National Wildlife Research Centre; Ottawa ON K1A 0H3 Canada
2. Department of Zoology; University of Manitoba; Winnipeg MB R3T 2N2 Canada
3. Department of Biology; University of Ottawa; Ottawa ON K1N 6N5 Canada
4. Department of Mathematics and Statistics; University of Ottawa; Ottawa ON K1N 6N5 Canada
5. Biosciences; Swansea University; Swansea SA2 8PP UK