DBIO &CESAM-Centre for Environmental and Marine Studies, University of Aveiro, Aveiro, Portugal.
South Iceland Research Centre, University of Iceland, Fjolheimar IS-800 Selfoss &IS-861 Gunnarsholt, Iceland.
Sci Rep. 2016 Nov 30;6:38154. doi: 10.1038/srep38154.
Landbirds undertaking within-continent migrations have the possibility to stop en route, but most long-distance migrants must also undertake large non-stop sea crossings, the length of which can vary greatly. For shorebirds migrating from Iceland to West Africa, the shortest route would involve one of the longest continuous sea crossings while alternative, mostly overland, routes are available. Using geolocators to track the migration of Icelandic whimbrels (Numenius phaeopus), we show that they can complete a round-trip of 11,000 km making two non-stop sea crossings and flying at speeds of up to 24 m s(−1); one of the fastest recorded for shorebirds flying over the ocean. Although wind support could reduce flight energetic costs, whimbrels faced headwinds up to twice their ground speed, indicating that unfavourable and potentially fatal weather conditions are not uncommon. Such apparently high risk migrations might be more common than previously thought, with potential fitness gains outweighing the costs.
内陆迁徙的陆鸟有可能在途中停留，但大多数长途迁徙者还必须进行长时间的不停歇的跨海迁徙，其长度差异很大。对于从冰岛迁徙到西非的涉禽来说，最短的路线将涉及最长的连续跨海迁徙，而替代的、主要是陆路的路线是可用的。我们使用地理定位器来追踪冰岛杓鹬（Numenius phaeopus）的迁徙，结果表明它们可以完成 11000 公里的往返飞行，进行两次不停歇的跨海迁徙，飞行速度高达 24 米/秒；这是在海洋上空飞行的涉禽中记录到的最快速度之一。尽管风力支持可以降低飞行的能量成本，但杓鹬面临的逆风速度是其地面速度的两倍，这表明不利的、可能致命的天气条件并不罕见。这种明显高风险的迁徙可能比以前认为的更为普遍，潜在的适应收益超过了成本。
