Dataset: Cool birds: First evidence of energy-saving nocturnal torpor in free-living common swifts Apus apus resting in their nests

Daily torpor is a means of saving energy by controlled lowering of the metabolic rate (MR) during resting, usually coupled with a decrease in body temperature. We studied nocturnal daily torpor under natural conditions in free-living common swifts Apus apus resting in their nests as a family using two non-invasive approaches. First, we monitored nest temperature (Tnest) in up to 50 occupied nests per breeding season in 2010-2015. Drops in Tnest were the first indication of torpor. Among 16,673 observations, we detected 423 events of substantial drops in Tnest of on average 8.6°C. Second, we measured MR of the families inside nest boxes prepared for calorimetric measurements during cold periods in the breeding seasons of 2017 and 2018. We measured oxygen consumption and carbon dioxide production using a mobile indirect respirometer and calculated the percentage reduction in MR. During six torpor events observed, MR was gradually reduced by on average 56% from the reference value followed...每日蛰伏（Daily torpor）是动物在静息状态下通过主动调控降低代谢率（metabolic rate, MR）以节约能量的生理策略，通常伴随体温下降。本研究针对自然环境中以家族为单位在巢内静息的野生普通雨燕（Apus apus）的夜间每日蛰伏行为，采用两项非侵入式方法（non-invasive approaches）开展观测。其一，我们于2010至2015年的每个繁殖季，对最多50个活跃巢箱开展巢温（nest temperature, Tnest）监测；巢温下降是蛰伏发生的初步信号。在总计16673次观测中，我们共检测到423次巢温显著下降事件，平均降幅达8.6℃。其二，我们在2017和2018年繁殖季的寒冷时段，对巢箱内的雨燕家族开展代谢率测量，实验采用量热测量法（calorimetric measurements）；我们使用移动式间接呼吸仪（mobile indirect respirometer）测定其耗氧量与二氧化碳产生量，并计算代谢率的降低百分比。在观测到的6次蛰伏事件中，代谢率较参考值平均降低了56%，随后……