Northeastern Naturalist 554 T.S. Fredericksen 2014 Vol. 21, No. 4 NORTHEASTERN NATURALIST 2014 21(4):554–564 Thermal Regulation and Habitat Use of the Eastern Box Turtle in Southwestern Virginia Todd S. Fredericksen * Abstract - While Terrapene carolina carolina (Eastern Box Turtle) are found over a wide geographic range, they appear to select microhabitats based on the need for thermo- regulation, minimization of water loss, and reproduction. Habitat selection and the activity patterns of Eastern Box Turtles in southwestern Virginia were studied in relation to short- term weather conditions and seasonal variation. Turtles were located using telemetry 36% of the time in the interior of mature forest habitats, 23% in edge habitats, 18% in felds, 7% in a 22-year-old Pinus strobus (Eastern White Pine) plantation, 7% in forest canopy gaps, 5% in a 4-year-old clearcut, and 4% in streams. We observed a seasonal shift in habi- tat use, with more turtles using mature forest habitat compared to other habitat types in all months, except for May when 47% of all turtles were located in edge habitat. Also, Eastern Box Turtles often selected canopy gaps within forests during the fall, and females moved from forests to recent clearcuts during the nesting season, which accounted for a larger home-range size. As expected, turtle activity was lower during hot, dry periods in mid- summer and decreased gradually during the autumn with decreasing temperature. Rainfall increased turtle activity, especially when following prolonged dry periods. Introduction Terrapene carolina carolina L. (Eastern Box Turtle) is a common terrestrial turtle found throughout the eastern United States. The geographic range closely coincides with that of the eastern deciduous forest (Dodd 2001), but Eastern Box Turtles may select microhabitats within or outside of forests for behaviors such as thermoregulation or nesting. Like most ectotherms, Eastern Box Turtles enter a state of torpor during winter months. In spring and summer, Eastern Box Turtles spend most of their time in forests, but will often venture into open habitats in search of food, and for basking and nesting (Dodd 2001). While Eastern Box Turtles are found in a wide range of macrohabitats, they appear to select microhabitats based on the need for thermoregulation and to minimize water loss (Ernst 1968, Rossell et al. 2006). As ectotherms, Eastern Box Turtles must maintain temperature homeostasis by seeking cover, such as shaded forests or streams, when body temperatures are high and by fnding basking loca- tions when body temperatures are low, in order to increase their metabolic rate for foraging and digestion. Ernst et al. (1994) noted that Eastern Box Turtles generally select microhabitats that maintain body temperatures of 29–38 ºC. Outside of this temperature range, Eastern Box Turtles may seek cover under leaf litter or vegeta- tion, called a “form” (sensu Stickel 1950) and, in the case of high temperatures and drought, turtles may enter water bodies for thermoregulation and to prevent dehydration (Donaldson and Echternacht 2005). * Ferrum College, Ferrum, VA 24088; tfredericksen@ferrum.edu. Manuscript Editor: Thomas Maier