1. Dept of Biological Sciences; Univ. of Alberta; Edmonton T6G 2E9 Canada
2. Applied Animal Ecology, Inst. for Conservation Research, San Diego Zoo Global; San Diego CA 92112 USA
3. Polar Bears International; Winnipeg R2W 5K8 Canada
4. Wildlife Research Division, Science and Technology Branch, Environment and Climate Change Canada; Edmonton T6G 2E9 Canada