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Although temperature is acknowledged as a driver of galliform population dynamics and individual behavior, the mechanisms behind these relationships are unclear. For example, the influence of thermal landscape patterns on northern bobwhite (Colinus virginianus) site selection during critical life history periods is poorly understood. We assessed black bulb temperatures (Tbb) and vegetation parameters at 87 bobwhite nests and paired microsites, and 38 brood locations at the Packsaddle Wildlife Management Area in western Oklahoma during 2013 and 2014. To characterize the thermal landscape, we also sampled Tbb and vegetation at 205 points that were distributed by vegetation type using a stratified random sampling approach. We found that the thermal landscape exhibited substantial heterogeneity, demonstrated by differences in Tbb up to 40??C during peak diurnal heating. Nest and brood sites selected by bobwhites moderated Tbb by more than 5??C and 10??C compared to the surrounding landscape, respectively. Additionally, on days experiencing ambient temperatures ? 39??C, successful nests were on average 6??C cooler than unsuccessful nests. During peak diurnal heating, broods behaviorally modified their thermal exposure by curtailing movement and seeking shelter in patches of tall densely canopied woody cover. However, concomitant to climate change scenarios, our modeled Tbb measurements suggest that thermal environments will become more extreme and will occur for longer portions of the day, potentially increasing thermal constraints on bobwhite behavior and site selection. These findings suggest that future conservation efforts should include the maintenance of thermal complexity at scales relevant to ground-dwelling birds. Furthermore, they underscore that rangeland landscapes should be viewed as dynamic thermal mosaics which influence site selection during critical reproductive stages and highlight the ecological relevance of landscapes as moderators of thermal extremes.