Helbig Andreas J
Institut für Pharmazeutische Biologie, Universität Heidelberg, Im Neuenheimer Feld 364, W-6900, Heidelberg, Federal Republic of Germany.
Oecologia. 1992 Jul;90(4):483-488. doi: 10.1007/BF01875441.
Blackcaps (Sylvia atricapilla) from five areas in Central Europe were hand-raised. Their autumn migratory orientation was tested in funnel-shaped cages. Their directional choices were compared to recoveries of conspecifics ringed during the breeding season in the same areas, which are situated on a transect across a migratory divide between southeastward and southwestward migrating populations. Results from ringing and orientation tests were in good agreement with respect to mean direction and dispersion of flight directions. An exception is the area around Linz (NW Austria), right on the migratory divide, where ringing yielded a strong scatter, but hand-raised birds chose westerly directions. The recent establishment of a novel migration route toward the British Isles was reflected in both data sets: in southern Germany the percentage of northwestward migrants is 6.8% according to orientation tests and 11.8% according to ringing recoveries. Testing the orientation of young passerines in captivity can yield valuable information about population differentiation of migratory behaviour. It is more efficient than ringing in this respect, because it circumvents the low recovery rates and is free of biases affecting ringing data. In the blackcap, geographic differentiation of migratory directions occurs on a finer scale than previously recognized and can change significantly within 2-3 decades.
来自中欧五个地区的黑头莺（Sylvia atricapilla）由人工饲养长大。它们秋季的迁徙方向在漏斗形笼子中进行了测试。将它们的方向选择与在同一地区繁殖季节环志的同物种鸟类的回收情况进行了比较，这些地区位于一条横跨向东南和向西南迁徙种群之间迁徙分界线的样带上。环志和方向测试的结果在飞行方向的平均方向和离散度方面高度一致。位于迁徙分界线上的奥地利西北部林茨周围地区是个例外，在那里环志结果呈现出很大的离散度，但人工饲养的鸟类选择了向西的方向。两个数据集都反映了最近朝向不列颠群岛的新迁徙路线的形成：在德国南部，根据方向测试，向西北迁徙的鸟类比例为6.8%，根据环志回收数据则为11.8%。测试圈养条件下幼龄雀形目鸟类的方向选择能够提供有关迁徙行为种群分化的宝贵信息。在这方面，它比环志更有效，因为它避免了低回收率问题，且不受影响环志数据的偏差的干扰。在黑头莺中，迁徙方向的地理分化比之前认为的更为细微，并且在2到3十年内可能会发生显著变化。
