Factors affecting stopover duration in birds are still much discussed. Field studies report contradictory evidence regarding the effect of fuel reserves on bird decision to depart from a stopover site, while the majority of laboratory tests performed on passerines reported a positive relationship between body conditions and migratory restlessness. In recent years, a few studies integrating laboratory and field investigations suggested that the amount of migratory restlessness could be a proxy of the individual willingness to depart from a stopover site in night-migrating passerines, but similar studies are lacking for other groups of birds. In this paper the factors affecting stopover length in the Wood sandpiper Tringa glareola (Charadriiformes Scolopacidae) were studied by integrating field observations and laboratory tests during spring migration. Our aims were to investigate (1) the influence of body conditions on migratory restlessness and (2) the influence of body conditions and of the amount of migratory restlessness on stopover duration, after controlling for meteorological conditions. Contrary to our expectations, we did not find any relationship between body condition and migratory restlessness nor stopover duration, while for the 1st time in a non-passerine species, evidence was produced that the amount of migratory restlessness is significantly related to the likelihood of leaving the stopover area. Our results emphasize the relevance of the studies integrating field and laboratory tests to understand the physiological and ecological factors affecting migratory behaviour in different bird species.

Highlights

Body conditions seem to be unrelated both to migratory restlessness and stopover duration.

Migratory restlessness predicts the likelihood of leaving the stopover site.

The quantification of migratory restlessness seems to be a useful tool for studying the effect of intrinsic and extrinsic factors on stopover behaviour in shorebirds.

中文翻译：

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伍德鹬Tringa glareola的迁徙不安和停留时间

影响鸟类中途停留时间的因素仍然有很多讨论。实地研究报告了关于燃料储备对鸟类决定离开中途停留地点的影响的相互矛盾的证据，而对雀类进行的大多数实验室测试报告了身体状况和迁徙不安之间的正相关关系。近年来，一些结合实验室和实地调查的研究表明，迁徙不安的程度可能代表个体愿意离开夜间迁徙雀鸟中途停留地点的意愿，但对其他鸟类群体缺乏类似的研究。本文研究了影响木材鹬Tringa glareola停留时间的因素（Charadriiformes Scolopacidae）通过在春季迁徙期间整合实地观察和实验室测试进行了研究。我们的目的是调查（1）身体状况对迁徙不安的影响和（2）在控制气象条件后，身体状况和迁徙不安的数量对中途停留时间的影响。与我们的预期相反，我们没有发现身体状况与迁徙不安和中途停留时间之间存在任何关系，而在非燕雀类物种中，第一次有证据表明迁徙不安的数量与离开的可能性显着相关中途停留区。

强调

身体状况似乎与迁徙不安和中途停留时间无关。

迁徙的不安预示着离开中途停留地点的可能性。

迁徙不安的量化似乎是研究内在和外在因素对滨鸟中途停留行为影响的有用工具。