Numerous avian taxa use torpor, which involves pronounced reductions in body temperature (T b ) to below normothermic levels. However, the occurrence of this phenomenon in owls (Strigidae) remains largely unknown. We investigated winter patterns of thermoregulation in the crepuscular 80-g pearlspotted owlet Glaucidium perlatum and the strictly nocturnal 61-g African scops-owl Otus senegalensis by obtaining telemetric measurements of skin temperature (T skin ) from free-ranging individuals in

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... Kalahari Desert of southern Africa. Pearlspotted owlets remained homeothermic throughout the study period, whereas African scops-owls routinely used shallow torpor, with T skin reduced by 3.3Њ-8.6ЊC (pooled mean, 5.3Њ ‫ע‬ ) below normothermic levels for 3-4 h after sunrise. The 1.1ЊC mean lowest T skin recorded in three African scops-owl individuals was . The thermoregulatory differences be-29.0Њ ‫ע‬ 0.1ЊC tween these two species may be related to their diets and activity patterns. African scops-owls are almost exclusively insectivorous and experience a marked reduction in food availability on cold winter nights. In contrast, pearl-spotted owlets have more flexible activity patterns and include larger or diurnal vertebrate prey in their diet.