Replication Data for: "Operative temperatures of Eastern Garter Snakes (Thamnophis sirtalis sirtalis) reveal a Goldilocks effect for habitat use"

Garter snakes (<i>Thamnophis spp.</i>) are the most widespread reptiles in North America. Despite occupying vastly different biogeoclimatic zones, evidence suggests that thermal preference has not diverged among populations or <i>Thamnophis</i> species. The use of flexible thermoregulatory behaviours and habitat use could account for stability in thermal preference in garter snakes. To shed light on how thermal decisions influence local habitat use by the eastern garter snake (<i>Thamnophis sirtalis sirtalis</i>), we measured the thermal profiles of three microhabitats that differ in canopy cover: open peat, mixed shrub, and closed forest. We installed operative temperature models that mimicked the thermal properties of living <i>T. s. sirtalis</i> to record environmental temperatures at a fine scale and assess habitat thermal quality. We also used coverboards to survey the habitat usage of <i>T. s. sirtalis</i>. While the open canopy offered the highest thermal quality, we recorded the greatest number of snakes in the mixed shrub which had a considerably lower thermal quality. Since environmental temperatures regularly exceeded the upper thermal limit of <i>T. s. sirtalis</i> in the open canopy, snakes might favour the use of habitats that minimise the odds of overheating. Therefore, open habitats potentially restrict snakes’ activity window and may not be thermally attractive. Our data show that <i>T. s. sirtalis</i> use habitats that vary in thermal quality, but this pattern is not as simple as warmer habitats are better. Rather, snakes preferentially seek areas that offer a mix of open and closed canopies to suit their thermoregulatory needs.