Smit Ben, McKechnie Andrew E
DST/NRF Centre of Excellence at the Percy FitzPatrick Institute, School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Wits 2050, South Africa.
Physiol Biochem Zool. 2010 Jan-Feb;83(1):149-56. doi: 10.1086/605457.
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 pearl-spotted 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 the Kalahari Desert of southern Africa. Pearl-spotted owlets remained homeothermic throughout the study period, whereas African scops-owls routinely used shallow torpor, with T(skin) reduced by 3.3 degrees -8.6 degrees C (pooled mean, 5.3+/- 1.1 degrees C) below normothermic levels for 3-4 h after sunrise. The mean lowest T(skin) recorded in three African scops-owl individuals was 29.0 degrees C +/- 0.1 degrees C. The thermoregulatory differences between 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.
许多鸟类分类群会进入蛰伏状态，这包括将体温（Tb）显著降低至低于正常体温水平。然而，这种现象在猫头鹰（鸱鸮科）中的发生情况仍 largely 未知。我们通过获取来自非洲南部喀拉哈里沙漠自由活动个体的皮肤温度（Tskin）遥测数据，研究了晨昏性的80克珍珠斑小鸮Glaucidium perlatum和严格夜行性的61克非洲角鸮Otus senegalensis的冬季体温调节模式。在整个研究期间，珍珠斑小鸮保持恒温，而非洲角鸮则经常使用浅蛰伏状态，日出后3至4小时，其皮肤温度（Tskin）比正常体温水平降低3.3摄氏度至8.6摄氏度（合并平均值为5.3±1.1摄氏度）。在三只非洲角鸮个体中记录到的平均最低皮肤温度为29.0摄氏度±0.1摄氏度。这两个物种之间的体温调节差异可能与其饮食和活动模式有关。非洲角鸮几乎完全以昆虫为食，在寒冷的冬夜食物供应量会显著减少。相比之下，珍珠斑小鸮的活动模式更灵活，其饮食中包括更大或日间的脊椎动物猎物。
