The breeding period is a demanding and time-constrained phase for migratory bird species. Breeding outcome and duration can interact with the extent and duration of post-breeding movements, resulting in individual differences in space use ultimately influencing later stages of the annual cycle. We present space-use and home range estimates during the breeding season for 21 European rollers Coracias garrulus tracked between 2018 and 2022, in Italy and Croatia. Using high-resolution spatial GPS data coupled with regular nest box monitoring, we analysed differences in space use during the incubation/nestling period vs post-breeding period prior to migration, accounting for the breeding outcome (successful vs failure). We found that adult movements were strongly reduced during the first phase, while increased in the post-breeding phase, especially for failed breeders. Successful breeders remained in the surroundings of the nest site, while unsuccessful ones tended to abandon the nest and visit distant areas (up to 500 km) for long periods (60.5 ± 6.2 days). Breeding outcome did not influence the departure date of autumn migration, suggesting that failed breeders used this period for exploratory movements but not for advancing the onset of migration. Such exploratory movements may be functional to prospect and inform settlement decisions in failed breeders in search of new breeding opportunities and may be particularly important in migratory species, which generally have a limited period to gather information prior to autumn migration. The study demonstrates the need to investigate seasonal movements in different populations and the potential importance of prospecting post-breeding movements for long-distance migratory species.

中文翻译：

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育种阶段和结果决定迁移前欧洲滚筒 Coracias garrulus 的空间利用

繁殖期对候鸟物种来说是一个要求苛刻且时间有限的阶段。育种结果和持续时间可以与育种后运动的范围和持续时间相互作用，导致空间利用的个体差异最终影响年度周期的后期阶段。我们展示了 2018 年至 2022 年间在意大利和克罗地亚追踪的 21 只欧洲鼯鳅 Coracias garrulus 在繁殖季节的空间使用和活动范围估计。使用高分辨率空间 GPS 数据与常规巢箱监测相结合，我们分析了孵化/雏鸟期与迁徙前繁殖后时期空间利用的差异，解释了繁殖结果（成功与失败）。我们发现成年运动在第一阶段大大减少，而在繁殖后阶段增加，特别是对于失败的育种者。成功的繁殖者留在巢穴周围，而不成功的繁殖者往往会放弃巢穴并长时间（60.5 ± 6.2 天）访问遥远的地区（最多 500 公里）。育种结果不影响秋季迁徙的出发日期，这表明失败的育种者利用这段时间进行探索性运动，而不是促进迁徙的开始。这种探索性运动可能有助于寻找失败的育种者寻找新的繁殖机会并为定居点决策提供信息，并且可能对迁徙物种特别重要，因为迁徙物种通常在秋季迁徙前收集信息的时间有限。