Chappell J
J Exp Biol. 1997;200(Pt 16):2269-77. doi: 10.1242/jeb.200.16.2269.
Clock-shifting (altering the phase of the internal clock) in homing pigeons leads to a deflection in the vanishing bearing of the clock-shifted group relative to controls. However, two unexplained phenomena are common in clock-shift experiments: the vanishing bearings of the clock-shifted group are often more scattered (with a shorter vector length) than those of the control group, and the deflection of the mean bearing of the clock-shifted group from that of the controls is often smaller than expected theoretically. Here, an analysis of 55 clock-shift experiments performed in four countries over 21 years is reported. The bearings of the clock-shifted groups were significantly more scattered than those of controls and less deflected than expected, but these effects were not significantly different at familiar and unfamiliar sites. The possible causes of the effects are discussed and evaluated with reference to this analysis and other experiments. The most likely causes appear to be conflict between the directions indicated by the sun compass and either unshifted familiar visual landmarks (at familiar sites only) or the unshifted magnetic compass (possible at both familiar and unfamiliar sites).
对信鸽进行时钟移位（改变生物钟的相位）会导致时钟移位组的消失方位相对于对照组发生偏移。然而，在时钟移位实验中通常存在两个无法解释的现象：时钟移位组的消失方位往往比对照组更分散（矢量长度更短），并且时钟移位组平均方位相对于对照组的偏移量往往比理论预期的要小。在此，报告了对在21年期间于四个国家进行的55次时钟移位实验的分析。时钟移位组的方位明显比对照组更分散，且偏移量比预期的要小，但在熟悉和不熟悉的地点，这些效应没有显著差异。结合该分析及其他实验对这些效应的可能原因进行了讨论和评估。最可能的原因似乎是太阳罗盘指示的方向与未移位的熟悉视觉地标（仅在熟悉地点）或未移位的磁罗盘（在熟悉和不熟悉地点均有可能）所指示的方向之间存在冲突。
