1994-present Assistant Unit Leader (Wildlife), Iowa Cooperative Fish and Wildlife Research Unit, Assistant professor, Dept. Animal Ecology, Iowa State University, Ames, Iowa
1993-94 Wildlife Biologist (Research), National Biological Survey
1987-93 Wildlife Biologist (Research), U.S. Fish and Wildlife Service
1983-86 Post-doctoral Research Associate, SUNY-Albany
1982-83 Visiting Assistant Professor, Dept. of Biology, Idaho State Univ.
1981 Visiting Lecturer, Dept. of Biology, Univ. of California, San Diego
1979-80 Post-graduate Research Biologist, Univ. of California, San Diego
1973-79 University of California, Berkeley; Museum of Vertebrate Zoology