Paclík Martin, Weidinger Karel
Laboratory of Ornithology, Palacký University, Olomouc, Czech Republic.
Int J Biometeorol. 2007 Mar;51(4):287-93. doi: 10.1007/s00484-006-0067-2. Epub 2007 Jan 9.
We examined the relationships between cavity temperature, ambient temperature outside the cavity and structural characteristics of 70 cavities measured for 1 night to determine if cavity roosting birds may potentially select warmer tree cavities for wintertime roosting. The mean temperature increment of the cavity (=cavity-ambient temperature) varied from -2.4 to 4.9 degrees C and increased with higher day-to-night fluctuations in the ambient temperature, smaller cavity entrance and better health status of the cavity tree. Cavities in healthy trees were warmer than those in dead trees, but this difference disappeared with rising mean ambient temperatures. This interaction between the effects of tree health status and mean ambient temperature, as well as the effect of day-to-night fluctuations in the ambient temperature, were supported by the analysis of repeated measurements of temperature taken on 12 consecutive nights in five cavities. The variability in cavity microclimates makes the selection of warmer roost sites possible, and the predictors of microclimate may provide indirect cues to prospecting birds.
我们研究了70个树洞在夜间测量的腔体温、树洞外环境温度与结构特征之间的关系，以确定树洞栖息鸟类是否可能在冬季选择较温暖的树洞栖息。树洞的平均温度增量（=腔体温-环境温度）在-2.4至4.9摄氏度之间变化，并随着环境温度的昼夜波动较大、树洞入口较小以及树洞树木的健康状况较好而增加。健康树木中的树洞比死亡树木中的树洞温度更高，但随着平均环境温度的升高，这种差异消失了。对五个树洞连续12个晚上进行的温度重复测量分析支持了树木健康状况和平均环境温度的影响之间的这种相互作用，以及环境温度昼夜波动的影响。树洞微气候的变异性使得选择较温暖的栖息地点成为可能，微气候的预测因素可能为觅食鸟类提供间接线索。
