1. Department of Ecology; Evolution and Behavior; University of Minnesota; St. Paul MN 55108 USA
2. Spatial Ecology & Epidemiology Group; Department of Zoology; University of Oxford; Oxford OX1 3PS UK
3. Recanati-Kaplan Centre/WildCRU; Department of Zoology; University of Oxford; Tubney OX13 5QL UK
4. Research Institute for the Environment & Livelihoods; Charles Darwin University; Casuarina NT 0909 Australia
5. Department of Ecology & Evolution; Imperial College London, London, SW7 2AZ, UK
6. Alberta Biodiversity Monitoring Institute; University of Alberta; Edmonton AB T6G 2E9 Canada
7. Department of Wildland Resources & Ecology Center; Utah State University; Logan UT 84322 USA