Predation prey games in the evolutionary ecology of migratory species

大多数关于鸟类和其他动物的迁徙路线、迁徙时间和在繁殖地或非繁殖地定居的研究集中在与食物和天气的季节性模式的关系上。这项研究考虑了移动捕食者对猎物迁徙行为的几个方面的影响，反之亦然。捕食者和猎物都应该分布自己，以最大限度地繁殖和生存，这两组运动相互作用，在某些情况下导致稳定的模式。正在研究这些动态结果的主要系统是在北极繁殖并在温带和热带海岸线过冬的小型琵鹭，以及它们的猎鹰捕食者。自从几乎禁止滴滴涕以来，北美和欧洲的猎鹰数量一直在稳步增加，这为评估猎物行为的变化提供了一个“自然实验”。随着世界变得更加危险，我们研究了猎鹰和琵琶如何在越冬地点重新分布，验证了在更安全但可能更缺乏食物的地区会发现更多琵鹭的预测。我们还测试了猎鹰是否会迁徙到不同的纬度，从而使更北的地方比更南边的地方对猎物更危险，以及主要由于身体大小的差异，具有不同脆弱性的琵鹭也会迁徙到不同的纬度。

Most research on the migration routes, timing of movements, and settlement on breeding or non-breeding grounds of birds and other animals concentrates on relationships with seasonal patterns of food and weather. This research considers the effects of mobile predators on several aspects of migration behaviour of their prey, and vice versa. Both predators and prey should distribute themselves to maximize their reproduction and survivorship, and the two sets of movements interact, in some cases leading to stable patterns. The principle systems where the outcomes of these dynamics are being studied are small sandpipers that breed in the arctic and spend the winter along temperate and tropical coastlines, and their falcon predators. Since the near banning of DDT, falcon populations have steadily increased in North America and Europe, providing a "natural experiment" against which changes in prey behaviour may be assessed. We examine how both falcons and sandpipers have redistributed themselves among wintering sites as the world has become more dangerous for the sandpipers, testing the prediction that more sandpipers will be found at safer, but perhaps more food-poor areas. We also test whether falcons migrate to different latitudes such that more northerly locations are more dangerous for prey than more southerly ones, and how sandpipers with different vulnerabilities, primarily because of differences in body sizes, also migrate to different latitudes.