Muheim Rachel, Phillips John B, Akesson Susanne
Department of Animal Ecology, Lund University, Ecology Building, SE-223 62 Lund, Sweden.
Science. 2006 Aug 11;313(5788):837-9. doi: 10.1126/science.1129709.
Migratory songbirds use the geomagnetic field, stars, the Sun, and polarized light patterns to determine their migratory direction. To prevent navigational errors, it is necessary to calibrate all of these compass systems to a common reference. We show that migratory Savannah sparrows use polarized light cues from the region of sky near the horizon to recalibrate the magnetic compass at both sunrise and sunset. We suggest that skylight polarization patterns are used to derive an absolute (i.e., geographic) directional system that provides the primary calibration reference for all of the compasses of migratory songbirds.
迁徙鸣禽利用地磁场、恒星、太阳和偏振光模式来确定它们的迁徙方向。为防止导航错误，有必要将所有这些罗盘系统校准到一个共同的参考标准。我们发现，迁徙的萨凡纳麻雀在日出和日落时利用地平线附近天空区域的偏振光线索来重新校准磁罗盘。我们认为，天空光偏振模式被用来推导一个绝对（即地理）方向系统，该系统为迁徙鸣禽的所有罗盘提供主要的校准参考。
