What makes Alpine swift ascend at twilight? Novel geolocators reveal year-round flight behaviour
What makes Alpine swift ascend at twilight? Novel geolocators reveal year-round flight behaviour
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是什么让阿尔卑斯雨燕在黄昏时升起？
DOI：
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发表时间：
2018
影响因子：
2.3
通讯作者：
F. Liechti
中科院分区：
文献类型：
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作者：
C. Meier;Hakan Karaardıç;R. Aymí;Strahil G. Peev;Erich Bächler;R. Weber;Willem Witvliet;F. Liechti
全年研究个体飞行行为对于了解鸟类的生态是必不可少的。最近的技术发展使我们能够在整个年度周期内跟踪小型长途候鸟的飞行行为。在少数研究中记录了鸟类黄昏上升的特定飞行行为，但仅在一年中的短时间内，从未在个体水平上量化。有人认为，黄昏上升可能是在方向和导航的作用。以前的研究只报道了繁殖地附近和迁徙期间的行为。我们调查了全年的飞行行为的34个单独的高山雨燕（Apus melba）的四个不同的人口在黄昏上升。我们记录了全年的黄昏上升，并发现在非洲非繁殖居住阶段的上升频率比一年中的所有其他阶段高出两倍。黎明上升是黄昏上升的两倍，主要发生在大气条件保持稳定超过24小时。我们没有发现确凿的证据证明黄昏上升对于重新校准指南针线索和地标是必不可少的。翅膀拍打强度的数据显示，黄昏时的高活动比上升时更有规律。因此，我们的结论是，高山雨燕一般增加飞行活动，也水平飞行，在黄昏期间，我们假设，这种增加的飞行活动，包括上升，可能是社会之间的相互作用individuals.Significance statementYear-round飞行高度跟踪与重量轻的多传感器标签揭示，高山雨燕上升几百米高黄昏定期。这种行为的原因尚不清楚，而且一天中这个时候的低光条件排除了觅食的可能性。黄昏上升的频率和高度是最高的非繁殖期，中间在迁移和低的积极繁殖者在繁殖阶段。我们讨论了我们的研究结果的背景下，现有的假设黄昏上升，我们提出了一个额外的假设，将黄昏上升与羊群成员之间的社会互动。我们的研究强调了如何飞行行为的候鸟物种的个人可以研究，即使在记录稀少的非繁殖期。
Studying individual flight behaviour throughout the year is indispensable to understand the ecology of a bird species. Recent development in technology allows now to track flight behaviour of small long-distance bird migrants throughout its annual cycle. The specific flight behaviour of twilight ascents in birds has been documented in a few studies, but only during a short period of the year, and never quantified on the individual level. It has been suggested that twilight ascents might be a role in orientation and navigation. Previous studies had reported the behaviour only near the breeding site and during migration. We investigated year-round flight behaviour of 34 individual Alpine swifts (Apus melba) of four different populations in relation to twilight ascents. We recorded twilight ascents all around the year and found a twofold higher frequency in ascents during the non-breeding residence phase in Africa compared to all other phases of the year. Dawn ascents were twice as common as dusk ascents and occurred mainly when atmospheric conditions remained stable over a 24-h period. We found no conclusive support that twilight ascents are essential for recalibration of compass cues and landmarks. Data on the wing flapping intensity revealed that high activity at twilight occurred more regularly than the ascents. We therefore conclude that alpine swift generally increase flight activity—also horizontal flight—during the twilight period and we suppose that this increased flight activity, including ascents, might be part of social interactions between individuals.Significance statementYear-round flight altitude tracking with a light-weight multi-sensor tag reveals that Alpine swifts ascend several hundred meters high at twilight regularly. The reason for this behaviour remains unclear and the low-light conditions at this time of the day preclude foraging as a possibility. The frequency and altitude of twilight ascents were highest during the non-breeding period, intermediate during migration and low for active breeders during the breeding phase. We discuss our findings in the context of existing hypotheses on twilight ascent and we propose an additional hypothesis which links twilight ascent with social interaction between flock members. Our study highlights how flight behaviour of individuals of a migratory bird species can be studied even during the sparsely documented non-breeding period.