Chernetsov Nikita, Kishkinev Dmitry, Mouritsen Henrik
Biological Station Rybachy, Zoological Institute of the Russian Academy of Sciences, Rybachy 238535, Kaliningrad Region, Russia.
Curr Biol. 2008 Feb 12;18(3):188-90. doi: 10.1016/j.cub.2008.01.018. Epub 2008 Jan 31.
In order to perform true bicoordinate navigation, migratory birds need to be able to determine geographic latitude and longitude. The determination of latitude is relatively easy from either stellar or magnetic cues [1-3], but the determination of longitude seems challenging [4, 5]. It has therefore been suggested that migrating birds are unable to perform bicoordinate navigation and that they probably only determine latitude during their return migration [5]. However, proper testing of this hypothesis requires displacement experiments with night-migratory songbirds in spring that have not been performed. We therefore displaced migrating Eurasian reed warblers (Acrocephalus scirpaceus) during spring migration about 1000 km toward the east and found that they were correcting for displacements by shifting their orientation from the northeast at the capture site to the northwest after the displacement. This new direction would lead them to their expected breeding areas. Our results suggest that Eurasian reed warblers are able to determine longitude and perform bicoordinate navigation. This finding is surprising and presents a new intellectual challenge to bird migration researchers, namely, which cues enable birds to determine their east-west position.
为了进行真正的双坐标导航，候鸟需要能够确定地理纬度和经度。从恒星或磁场线索中确定纬度相对容易[1 - 3]，但确定经度似乎具有挑战性[4, 5]。因此，有人提出候鸟无法进行双坐标导航，它们可能在春季返程迁徙时仅能确定纬度[5]。然而，要对这一假设进行恰当测试，需要对春季夜间迁徙的鸣禽进行位移实验，而此类实验尚未开展。因此，我们在春季迁徙期间将正在迁徙的欧亚苇莺（Acrocephalus scirpaceus）向东位移了约1000公里，发现它们通过将方向从捕获地点的东北方向转变为位移后的西北方向来校正位移。这个新方向会引导它们前往预期的繁殖地。我们的结果表明，欧亚苇莺能够确定经度并进行双坐标导航。这一发现令人惊讶，也给鸟类迁徙研究人员带来了新的智力挑战，即哪些线索使鸟类能够确定它们的东西方向位置。
