Data from: Linking oceanographic conditions, migratory schedules and foraging behaviour during the non‐breeding season to reproductive performance in a long‐lived seabird

1. Studies of the mechanisms underlying climate-induced population changes are critically needed to better understand and accurately predict population responses to climate change. Long-lived migratory species might be particularly vulnerable to climate change as they are constrained by different climate conditions and energetic requirements during the breeding and non-breeding seasons. Yet, most studies primarily focus on the breeding season of these species lifecycle. Environmental conditions experienced in the non-breeding season may have downstream effects on the other stages of the annual lifecycle. Not investigating such effects may potentially lead to erroneous inferences about population dynamics. 2. Combining demographic and tracking data collected between 2006 and 2013 at Kerguelen Island on a long-lived migratory seabird, the Black-Browed Albatross (Thalassarche melanophris), we investigated the links between sea surface temperature during the non-breeding season and behavioural and phenological traits (at-sea behaviour and migratory schedules) while accounting for different responses between birds of different sex and reproductive status (previously failed or successful breeders). We then explored if variation in the foraging behaviour and timing of spring migration influenced subsequent reproductive performance. 3. Our results showed that foraging activity and migratory schedules varied by both sex and reproductive status suggesting different energetic requirements and constraints among individuals. Higher sea surface temperatures during late winter, assumed to reflect poor winter conditions, were associated with an earlier departure from the wintering grounds and an extended pre-breeding period. However, an earlier spring migration and an earlier return to Kerguelen grounds were associated with a lower breeding success. 4. Our results highlighted that behaviour during some periods of the non-breeding season, particularly towards the end of the wintering period and the pre-breeding period had a significant effect on the subsequent reproductive success. Therefore, caution needs to be given to all stages of the annual cycle when predicting the influence of climate on population dynamics.

1. 为更好地理解并精准预测种群对气候变化的响应，亟需开展气候驱动种群变化背后机制的相关研究。长寿迁徙物种可能尤其易受气候变化影响，因为它们在繁殖季与非繁殖季均受到不同气候条件与能量需求的约束。然而，绝大多数研究主要聚焦于该类物种生命周期中的繁殖季。非繁殖季所经历的环境条件，可能对年度生命周期的其他阶段产生后续效应；若未探究此类效应，则可能导致种群动态相关推论出现偏差。
2. 本研究结合2006年至2013年在凯尔盖朗群岛采集的长寿迁徙海鸟——黑眉信天翁（*Thalassarche melanophris*）的种群统计与追踪数据，探究了非繁殖季海表温度与行为、物候性状（海上行为与迁徙节律）之间的关联，并纳入了不同性别、繁殖状态（此前繁殖失败或成功的个体）间的响应差异。随后，本研究进一步探讨了觅食行为与春季迁徙时间的变化是否会影响后续繁殖表现。
3. 研究结果显示，觅食活动与迁徙节律因性别与繁殖状态而异，表明不同个体间存在不同的能量需求与约束条件。晚冬季更高的海表温度（被认为反映了较差的冬季环境）与更早离开越冬地、延长的繁殖前期相关。然而，春季迁徙更早、更早返回凯尔盖朗群岛海域的个体，其繁殖成功率更低。
4. 本研究结果表明，非繁殖季部分阶段——尤其是越冬末期与繁殖前期的行为，会对后续繁殖成功率产生显著影响。因此，在预测气候对种群动态的影响时，需关注年度生命周期的所有阶段。