Seasonal migration is a common phenomenon in animals and connects geographically distant ecosystems. Considerable variation has been documented in this behaviour and migratory divides (contact zones between populations that use different routes to navigate around ecological barriers) are an example of this. Migratory divides could have important implications for ecological speciation as hybrids in divides take intermediate routes and it has been predicted that these routes will be ecologically inferior as they bring hybrids over barriers that parental forms avoid. We provide the first test of this prediction here using a well-characterized divide between coastal and inland subspecies of Swainson’s thrushes.

中文翻译：

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鸣禽迁徙鸿沟中栖息地适宜性和景观连通性降低

季节性迁徙是动物的常见现象，将地理上遥远的生态系统联系起来。在这种行为中已经记录了相当大的变化，迁徙鸿沟（使用不同路线绕过生态障碍的种群之间的接触区）就是一个例子。迁徙鸿沟可能对生态物种形成产生重要影响，因为鸿沟中的杂种采取中间路线，并且据预测，这些路线在生态上会较差，因为它们将杂种带到亲本避免的障碍上。我们在这里使用斯温森画眉的沿海和内陆亚种之间的明确划分提供了对这一预测的第一个测试。