Finding Mammals Using Far-Infrared Thermal Imaging

We examined the utility of far-infrared thermal imaging devices to detect and census mammals in the field. We used a Thermovision 210 to survey individuals, nests, or burrows of red squirrels (Tamiasciurus hudsonicus), arctic ground squirrels (Spermophilus parryii), snowshoe hares (Lepus americanus), and meadow jumping mice (Zapus hudsonius). Using far-infrared thermal imaging, we successfully detected free-ranging red squirrels, snowshoe hares, and meadow jumping mice. Thermal imaging also was highly successful in deter- mining activity at nests or burrows of Arctic ground squirrels. Far-infrared thermal imaging, however, was not useful in detecting active nests of red squirrels. These differences are largely attributable to variation among species in the insulative property of nests or fur. We review some of the limitations of far-infrared thermal imaging and conclude that it may provide a useful tool for certain ecological field studies.