McKechnie A E, Lovegrove B G
School of Botany and Zoology, University of Natal, Private Bag X01, Scottsville 3209, South Africa.
Physiol Biochem Zool. 2001 Mar-Apr;74(2):238-49. doi: 10.1086/319669.
Thermoregulation and the energetic significance of clustering behavior were assessed in the white-backed mousebird Colius colius. Basal metabolic rate was 40% below the predicted allometric values. Rest-phase body temperature (T(b)) was highly labile and as low as 26 degrees C. Rest-phase T(b) was not regulated with respect to a constant set point temperature, as occurs typically in endotherms. Rather, we observed periods of linear decreases in rest-phase T(b) at a rate dependent on ambient temperature (T(a)) and the number of individuals in a cluster. The apparent inability of individual mousebirds to maintain rest-phase homeothermy suggests that clustering behavior is obligatory in the defense of a rest-phase set point T(b). The low rest-phase body temperatures exhibited by single C. colius hence appear to represent a normothermic state rather than typical avian facultative hypothermia. The birds were able to make significant energy savings by means of clustering behavior. These energy savings were dependent on T(a) and the number of birds in the cluster. At a T(a) of 15 degrees C, the mean energy expenditure of each bird in a cluster of six was 50% of that of a single bird. The metabolic traits of C. colius are likely be adaptive in the arid habitats that this species inhabits.
对白背鼠鸟（Colius colius）的体温调节及集群行为的能量意义进行了评估。基础代谢率比预测的异速生长值低40%。休息阶段的体温（T(b)）极不稳定，低至26摄氏度。休息阶段的T(b)不像典型恒温动物那样相对于一个恒定的设定点温度进行调节。相反，我们观察到休息阶段T(b)呈线性下降的时期，其下降速率取决于环境温度（T(a)）和集群中的个体数量。单个鼠鸟明显无法维持休息阶段的体温恒定，这表明集群行为对于维持休息阶段的设定点T(b)是必不可少的。因此，单个白背鼠鸟在休息阶段表现出的低体温似乎代表一种正常体温状态，而非典型鸟类的适应性低温。这些鸟类能够通过集群行为显著节省能量。这些能量节省取决于T(a)和集群中的鸟类数量。在15摄氏度的T(a)条件下，六只鸟组成的集群中每只鸟的平均能量消耗是单只鸟的50%。白背鼠鸟的代谢特征可能适应于该物种所栖息的干旱栖息地。
