1. Department of Biology, Colorado State University, 1878 Campus Delivery, Fort Collins, CO 80523, USA.
2. Department of Fish, Wildlife, and Conservation Biology, Colorado State University, 1474 Campus Delivery, Fort Collins, CO 80523-1474, USA.
3. Department of Ecosystem Science and Management, University of Wyoming, 1000 East University Avenue, Laramie, WY 82071, USA.
4. U.S. Geological Survey, Fort Collins Science Center, 2150 Centre Avenue, Building C, Fort Collins, CO 80526, USA.