Patterns of Burrow Use by Desert Tortoises: Gender Differences and Seasonal Trends

Mitigation-driven translocation effects on temperature, condition, growth, and mortality of Mojave desert tortoise ( Gopherus agassizii ) in the face of solar energy development

“…We observed an increase in tortoise temperature with increasing environmental temperature, then leveling off at highest environmental temperatures, which likely corresponds with use of burrows to behaviorally thermoregulate (Bulova, 1994(Bulova, , 2002Rautenstrauch et al, 2002;Zimmerman et al, 1994). This pattern was consistent across all three groups, but with higher maximum daily temperatures and longer duration above 35°C for translocated than resident and control tortoises, particularly during the first month post-translocation.…”

Using motion-sensor camera technology to infer seasonal activity and thermal niche of the desert tortoise (Gopherus agassizii)

“…Strong selective forces may act upon male tortoises to increase mate searching activity (Bonnet et al, 2001). Male desert tortoises also increase burrow searching during the mating season (Bulova, 1994) and use larger home ranges (Duda et al, 1999). Increased activity in males, especially at suboptimal and supraoptimal temperatures, needs to be considered in future research monitoring of the desert tortoise, as increased anthropogenic-based hazards may occur outside of the optimal activity season in tortoises.…”

“…Several studies of the desert tortoise have used direct observational methods to examine daily and seasonal timing of activity (Averill-Murray et al, 2002;Luckenbach, 1982;Nagy and Medica, 1986;Osario and Bury, 1982;, air temperature activity ranges (Berry and Turner, 1986;Brattstrom, 1965;McGinnis and Voigt, 1971;Woodbury and Hardy, 1948;Zimmerman et al, 1994), and temperature thresholds for activity (Hutchinson et al, 1966;Naegle, 1976). However, few studies use indirect methods and constant activity temperature monitoring to examine activity patterns (i.e., thermal models, ibutton sensors) (Bulova, 1994;Nussear et al, 2007;Zimmerman et al, 1994).…”

Severe mortality of a population of threatened Agassiz’s desert tortoises: the American badger as a potential predator

“…Burrows are important features of the desert tortoises' environment, providing shelter from extreme temperatures, aridity, and predators, and act as sites of conspecific interaction and nesting (Woodbury & Hardy 1948, Turner et al 1986, Bulova 1994, Rostal et al 1994. Tortoises spend the majority of the year inactive in burrows or dens and are surface active primarily in the spring and late summer when forage and occasional water are available and high ambient temperatures do not preclude activity (Nagy & Medica 1986).…”

“…Tortoises dig burrows by alternately scraping at the end of the tunnel with each forelimb and pushing loose soil out through the entrance (Woodbury & Hardy 1948), resulting in a tunnel up to a few meters long of similar width and height as the individual tortoise and a raised 'apron' at the mouth of the burrow. Tortoises occupy multiple burrows throughout the year and a single burrow may be used by multiple tortoises, either synchronously or asynchronously (Bulova 1994).…”