1. U.S. Geological Survey Forest and Rangeland Ecosystem Science Center 3200 SW Jefferson Way Corvallis Oregon 97331 USA
2. Oregon Cooperative Fish and Wildlife Research Unit Department of Fisheries and Wildlife Oregon State University 104 Nash Hall Corvallis Oregon 97331 USA
3. U.S. Geological Survey Oregon Cooperative Fish and Wildlife Research Unit Department of Fisheries and Wildlife Oregon State University 104 Nash Hall Corvallis Oregon 97331 USA