The annual disappearance and reappearance of billions of migratory animals from seasonal environments across the planet is a stunning natural phenomenon. Naturalists have marveled for more than 2,000 y at these migrations, at least since Aristotle pondered birds’ seasonal disappearance. Birds are the preeminent seasonal commuters because of their physiological capacity for sustained long-distance flight, extraordinary navigational adaptations, and diversity of movement patterns; and since Aristotle’s time we have learned much about how and why birds migrate (1). What’s been tougher to decipher is how and where migrants’ populations are controlled. Sampling and tracking the millions of individuals in many species is challenging because of far-flung seasonal movements that can span entire continents and shuttle between them, the baffling array of ways to migrate, and the potential for population limitation in summer, winter, spring or fall transits, or some combination thereof. Overcoming many of these challenges, Kramer et al. (2) in PNAS contribute significantly to understanding migratory birds’ population bottlenecks by linking different distribution patterns in two closely related Vermivora wood warblers (Parulidae) to ecological conditions precipitating decline in a geographically distinctive population of one of the two species.

中文翻译：

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识别候鸟的时空瓶颈[生态]

每年从地球上的季节性环境中消失的数十亿只迁徙动物每年都会消失并重新出现，这是一种令人震惊的自然现象。至少自从亚里斯多德思考鸟类的季节性消失以来，博物学家对这些迁徙感到惊奇2000多年。鸟类是出色的季节性通勤者，因为它们具有持续长途飞行的生理能力，非凡的航行适应性和运动方式的多样性；自亚里士多德时代以来，我们已经学到了很多有关鸟类迁徙的方式和原因的信息（1）。难以解释的是如何以及在何处控制移民的人口。采样和跟踪许多物种中数以百万计的个体具有挑战性，这是因为可能跨越整个大陆并在它们之间穿梭的季节性季节性运动，令人困惑的迁移方式以及夏季，冬季，春季或夏季限制种群的潜力。秋季过境，或其组合。克服了许多挑战，Kramer等人。（2）在PNAS中，通过将两个紧密相关的Vermivora木莺（Parulidae）的不同分布模式与生态条件相联系，从而促进了候鸟的种群瓶颈，该生态条件加剧了这两个物种之一的地理上独特的种群数量的下降。