1. Oregon Cooperative Fish and Wildlife Research Unit; Department of Fisheries and Wildlife; Oregon State University; 104 Nash Hall Corvallis OR 97331 USA
2. U.S. Geological Survey; Oregon Cooperative Fish and Wildlife Research Unit; Department of Fisheries and Wildlife; Oregon State University; 104 Nash Hall Corvallis OR 97331 USA
3. Oregon State University; Department of Fisheries and Wildlife; 104 Nash Hall Corvallis OR 97331 USA
4. Oregon Department of Fish and Wildlife; 4034 Fairview Industrial Drive Salem OR 97302 USA