Data from: ‘Same procedure as last year?' Repeatedly tracked swifts show individual consistency in migration pattern in successive years

Individual migration pattern during non-breeding season is still a black
box in many migratory birds. However, knowledge on both individual level
and population level in migration and overwintering is fundamental to
understand the life cycle of these birds and the constraints affecting
them. We showed in a highly aerial migrant, the common swift Apus apus,
that repeatedly tracked birds breeding at one site in Germany used the
same individual-specific migration routes and wintering areas in
subsequent years. In contrast, different individuals from the same
breeding colony showed diverse movement patterns during non-breeding
season suggesting that several suitable areas for overwintering coexist.
We found lower variation in timing of autumn and spring migration within
than between individuals. Our findings provide first indication of
individual consistency but between-individual variation in migration
pattern in a small non-passerine bird revealed by geolocators. This
supports that swifts have diverse but individual-specific ‘step-by-step’
migration patterns revealing high flexibility through individual
strategies.

许多候鸟在非繁殖季节的个体迁徙模式仍是未解之谜。然而，了解候鸟在迁徙和越冬过程中的个体及种群层面信息，对于理解其生命周期及影响它们的限制因素至关重要。我们以高度依赖飞行的候鸟——普通雨燕（Apus apus）为研究对象发现，在德国某繁殖地繁殖、且被重复追踪的个体，在后续年份中使用相同的个体特异性迁徙路线和越冬地。相比之下，同一繁殖群体中的不同个体在非繁殖季节表现出多样化的活动模式，这表明存在多个适宜的越冬区域。我们发现，个体内部的春秋迁徙时间变异小于个体间的变异。我们的研究结果首次通过地理定位器（geolocators）揭示，小型非雀形目鸟类存在迁徙模式的个体一致性及个体间变异。这表明雨燕具有多样化但个体特异性的“逐步式”迁徙模式，其个体策略展现出高度灵活性。