Data from: Generational shift in spring staging site use by a long-distance migratory bird

In response to environmental change, species have been observed altering their migratory behaviours. Few studies, however, have been able to determine whether these alterations resulted from inherited, plastic, or flexible changes. Here we present a unique observation of a rapid population-level shift in migratory routes — over 300 km from Spain to Portugal — by continental black-tailed godwits Limosa limosa limosa. This shift did not result from adult godwits changing staging sites, as adult site use was highly consistent. Rather, the shift resulted from young godwits predominantly using Portugal over Spain. We found no differences in reproductive success or survival among individuals using either staging site, indicating that the shift resulted from developmental plasticity rather than natural selection. Our results therefore suggest that new migratory routes can develop within a generation and that young individuals may be the agents of such rapid changes.

已有观测显示，为应对环境变化，诸多物种正调整其迁徙行为。然而，鲜有研究能够明确这些行为改变究竟源于遗传决定、表型可塑性或是灵活适应性变化。本研究报道了一项独特观测结果：大陆型黑尾塍鹬（Limosa limosa limosa）的种群级迁徙路线发生了快速偏移，其迁徙路线从西班牙偏移至300余公里外的葡萄牙。此次路线偏移并非由成鸟改变中途停歇地（staging sites）所致，因为成鸟对停歇地的使用始终保持高度一致。相反，该偏移源于幼鸟优先选择葡萄牙作为中途停歇地，而非西班牙。研究发现，使用两类中途停歇地的个体在繁殖成功率与存活率上均无显著差异，这表明此次路线偏移源于发育可塑性，而非自然选择。因此，本研究结果表明，全新的迁徙路线可在单一代际内形成，而幼鸟或许正是这类快速变化的推动者。