1. U.S. Geological Survey, New Mexico Cooperative Fish and Wildlife Research Unit, P.O. Box 30003 MSC 4901, Las Cruces, New Mexico 88003, USA
2. Animal Diseases Research Unit, USDA/ARS, Washington State University, 3003ADBF, Pullman, Washington 99164, USA
3. U.S. Army White Sands Missile Range, Environmental Stewardship Division, CSTE-DTC-ES, WSMR, New Mexico 88002, USA
4. Department of Fishery and Wildlife Sciences, New Mexico State University, Las Cruces, New Mexico 88003, USA