26th Annual Meeting and Symposium of the
Desert Tortoise Council, March 16-18, 2001
Abstracts

Activity and Behavior of Desert Tortoises in a Northeast Sonoran Desert Population

Roy C. Averill-Murray
Arizona Game and Fish Department, 2221 W Greenway Road, Phoenix, AZ 85023

Desert tortoises were monitored weekly with radio telemetry from 1996 through 1999 at a Sonoran Desert site on the Tonto National Forest, northeast of Phoenix, Arizona. Peak tortoise activity occurred during the summer monsoon season, but spring and winter activity increased with increasing rainfall during those seasons. Spring foraging appears to be important, especially for females, since ovarian follicles mature during spring. Males also appeared to be more active during spring than previously thought. Average annual home range areas ranged up to about 6 ha, but some individuals made long-distance movements outside their “normal” home ranges. Some of these movements represent temporary excursions to specific resource sites, such as nesting burrows. Others are more difficult to explain, but some may represent dispersal.