Walcott C, Gould J L, Lednor A J
Laboratory of Ornithology, Cornell University, Ithaca, NY 14850.
J Exp Biol. 1988 Jan;134:27-41. doi: 10.1242/jeb.134.1.27.
Homing pigeons appear to use the earth's magnetic field as a compass and perhaps as part of their position-finding system or 'map'. The sensory system they use to detect magnetic fields is unknown, but two current possibilities are some mode of response by the pineal organ or by the visual system, or it may be based on the magnetite crystals found in their heads. Three series of experiments to test the involvement of magnetite are reported here. The alignment of the permanent magnetic domains in the birds heads was altered by (a) demagnetizing the birds, (b) magnetizing them with a strong magnetic field and (c) exposing the birds to a strong magnetic gradient. None of these treatments had a marked effect on the pigeon's orientation or homing under sunny skies, but a few results obtained under overcast skies suggest that demagnetizing the birds may have increased the scatter of their vanishing bearings. Perhaps pigeons use one magnetic sensor for their magnetic compass and another for some component of the map.
信鸽似乎将地球磁场用作指南针，也许还作为其定位系统或“地图”的一部分。它们用于检测磁场的感觉系统尚不清楚，但目前有两种可能性，一是松果体器官或视觉系统的某种反应模式，二是可能基于在它们头部发现的磁铁矿晶体。本文报告了三组用于测试磁铁矿作用的实验。通过以下方式改变鸟类头部永久磁畴的排列：(a) 使鸟类消磁，(b) 用强磁场使它们磁化，(c) 将鸟类暴露在强磁梯度下。在晴朗天空下，这些处理方法均未对鸽子的定向或归巢产生显著影响，但在阴天获得的一些结果表明，使鸟类消磁可能会增加它们消失方向的离散度。也许鸽子使用一个磁传感器作为磁罗盘，另一个用于地图的某些组成部分。
