Patterns of Burrow Use by Desert Tortoises (Gopherus agassizii) in Southcentral Nevada

Kurt R. Rautenstrauch
Bechtel SAIC Company, LLC, 1180 Town Center Drive, Las Vegas, Nevada 89144 USA [E-mail: kurt_rautenstrauch@ypm.gov]

Danny L. Rakestraw
Science Applications International Corporation, 3960 Howard Hughes Parkway #200, Las Vegas, Nevada 89109 USA

Greg A. Brown
Bechtel SAIC Company, LLC, 1180 Town Center Drive, Las Vegas, Nevada 89144 USA
Present Address: JBR Environmental Consultants, 8160 S. Highland Drive, Sandy, Utah 89801 USA

James L. Boone
Bechtel SAIC Company, LLC, 1180 Town Center Drive, Las Vegas, Nevada 89144 USA

Patrick E. Lederle
Bechtel SAIC Company, LLC, 1180 Town Center Drive, Las Vegas, Nevada 89144 USA
Present Address: Michigan Department of Natural Resources, Wildlife Division, P.O. Box 30444, Lansing, Michigan 48909 USA

ABSTRACT

We monitored seasonal use of burrows and other cover by 113 radiomarked adult desert tortoises, Gopherus agassizii, at Yucca Mountain, Nevada, with 18,312 observations over 3 years. We found tortoises in burrows most often during the hottest and coldest months, and in pallets and away from cover most often during months with moderate temperatures. The number of burrows used annually (mean = 11.7, range = 4­-23) differed among some years and differed between sexes in one year. Males and females used an average of 5 and 3 deep burrows (length > 1 m) per year, respectively. Tortoises used an average of 5 new burrows per year, which was, on average, 39 to 52% of the burrows used annually. Most new burrows (80%) were shallow (length < 1 m), which suggests a relatively high turnover of shallow burrows. Relative to females, males were observed in deep burrows more often, used a greater number of deep burrows, and were deeper in burrows. Males and females also used a different number of burrows and different types of cover during spring and fall. These seasonal differences probably were related to the annual reproductive cycle.

KEY WORDS

Reptilia, Testudines, Testudinidae, Gopherus agassizii, Tortoise, Ecology, Behavior, Burrows, Thermoregulation, Nevada.

For a complete copy of the article, please see Chelonian Conservation and Biology, Volume 4, Number 2 (December 2002).