Centre for Biological Diversity, University of St Andrews, St Andrews, United Kingdom.
Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus.
PLoS One. 2022 Oct 19;17(10):e0273686. doi: 10.1371/journal.pone.0273686. eCollection 2022.
First time migrants (juveniles hereafter) of many species migrate without specific knowledge of non-breeding locations, but experience may aid adults in timing and route decisions because they can migrate more efficiently to their previous non-breeding sites. Consequently, we expect a transition to more efficient migratory behaviour with age, but when and how this happens is little known. We used light-level geolocator data from Cyprus wheatears Oenanthe cypriaca to compare migration timing and route directness between juveniles and adults, and repeatability of their timing and non-breeding locations. We predicted that juveniles would depart and arrive later than adults for both autumn and spring migration; that duration of migration would be greater for juveniles; that routes taken by juveniles would be less direct than those for adults; and that autumn and spring departure timing, and non-breeding locations, would be more repeatable for adults between two years than for juveniles between their first and subsequent migration. We found that juveniles departed significantly later than adults in autumn but there was no difference in arrival timing, and although spring departure timings did not differ, juveniles arrived on the breeding grounds later than adults. Nevertheless, we found no significant age-related difference in the duration of migration in autumn or spring. Yet, juvenile migrations were less direct than those of adults in autumn, but not spring. We found evidence that spring departure timing and non-breeding locations were repeatable for adults but not juveniles. Our findings show that age-related changes in migratory behaviour begin to occur during the first annual cycle demonstrating the potential for early adaptation to environmental variability within an individual's life.
首次迁徙的（以下简称幼鸟）许多物种在没有关于非繁殖地具体知识的情况下迁徙，但经验可能有助于成年鸟在时间和路线决策方面做出决策，因为它们可以更有效地迁徙到以前的非繁殖地。因此，我们预计随着年龄的增长，迁徙行为会变得更加高效，但这种转变何时以及如何发生还知之甚少。我们使用来自塞浦路斯麦田鸫 Oenanthe cypriaca 的光水平地理定位器数据，比较了幼鸟和成年鸟之间的迁徙时间和路线直接性，以及它们的时间和非繁殖地的可重复性。我们预测幼鸟在秋季和春季迁徙中的出发和到达时间都将晚于成年鸟；幼鸟的迁徙时间将更长；幼鸟的迁徙路线将不如成年鸟直接；并且，在两年之间，成年鸟的秋季和春季出发时间以及非繁殖地位置的可重复性将高于幼鸟第一次和随后迁徙之间的可重复性。我们发现幼鸟在秋季明显晚于成年鸟出发，但到达时间没有差异，尽管春季出发时间没有差异，但幼鸟比成年鸟更晚到达繁殖地。然而，我们没有发现秋季或春季迁徙时间与年龄相关的显著差异。然而，幼鸟的迁徙路线在秋季不如成年鸟直接，但在春季则不然。我们有证据表明，成年鸟的春季出发时间和非繁殖地位置是可重复的，但幼鸟则不是。我们的研究结果表明，迁徙行为的年龄相关变化在第一年的生命周期中就开始发生，这表明个体一生中存在对环境变化进行早期适应的潜力。
