29th Annual Meeting and Symposium of the
Desert Tortoise Council, February 20-23, 2004
Abstracts

Summer and Early Fall Activities of Adult Desert Tortoises at Fort Irwin, California: A Progress Report

Kristin H. Berry¹, Kemp Anderson², Tracy Bailey³, and Rachel Woodard^4
1U.S. Geological Survey, Western Ecological Research Center, 22835 Calle San Juan de Los Lagos, Moreno Valley, CA 92553
²324 ½ 15th Street, Seal Beach, CA 90740; ³619 Pinon Court, Ridgecrest, CA 93555; ⁴1539 N. China Lake Blvd., PMB 613, Ridgecrest, CA 93555

We have studied summer and early fall social behavior in desert tortoises at Fort Irwin since 1999. Our first project was to test hypotheses about effects of military maneuvers on tortoise activities and behavior at the Tiefort Mountains and a nearby control site. The control site has no military use and no appreciable human disturbance. Some tortoise activities differ significantly between the Tiefort Mountains and Control sites, and differences in activities can vary by sex and sizes of the tortoises. For example, tortoises at Tiefort spend significantly more time above ground, alone, and active than tortoises at Control. Our second project is focused on determining social structure and behaviors at the control site in summer and fall. We have identified three alpha males, recorded potential defense of resources by alpha males, and documented dominance hierarchies among males. We have observed numerous aggressive interactions, copulations and attempted copulations, and apparent patrolling and guarding behaviors. Our observations and preliminary findings have management applications for translocations, modeling of epidemiology of infectious diseases, and other recovery-related subjects.
Acknowledgements: We thank Mickey Quillman and the National Training Center at Fort Irwin for funding support.