Seasonal migration has evolved as an adaptation for exploiting peaks of resource abundance and avoiding unfavourable climatic conditions. Differential migratory strategies and choices of wintering areas by long‐distance migratory species may impose varying selective pressures and mortality risks with fitness consequences. Recently developed tracking technologies allow wintering movements of migratory species to be studied. However, these technologies typically involve a limited number of tracked individuals, which gives low statistical power for any robust estimate of survival probabilities. Additionally, when utilising geolocators, data become accessible only upon individual recapture, presenting a potential source of bias. We used multievent modelling to include information of 147 identified wintering tracks in the analysis of 1104 long‐term individual capture histories (2000–2022) of migratory seabird Calonectris diomedea and then test if individual preferences for wintering areas may drive heterogeneity in adult survival. We also examined individual fidelity to wintering areas and tested if climatic and oceanographic conditions, as represented by the wNAO and SOI climatic indices, influenced survival and fidelity. The probability of fidelity to a wintering area was ca. 0.79. Annual changes between areas were influenced by environmental variability driven by the wNAO. Survival probability was influenced by the SOI and differed between wintering areas; these differences coupled with high wintering site fidelity, generated individual heterogeneity in adult survival. Our study reveals that, over the last two decades, some individuals wintered in less suitable areas, with nonnegligible consequences on adult survival, the parameter to which the population growth rate is most sensitive in long‐lived species. Winter oceanographic conditions such as stormy weather or the proximity to upwellings probably play a relevant role in driving survival heterogeneity. Further research is needed to enhance our understanding of how the interlinked effects of climate, local selective pressures and individual condition shape population dynamics in migratory species.
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机译：季节性迁移已经演变为一种适应方式，以利用资源丰富的高峰期并避免不利的气候条件。长距离迁徙物种的差异性迁徙策略和越冬区的选择可能会带来不同的选择压力和死亡风险，从而产生适应性后果。最近开发的跟踪技术允许研究迁徙物种的越冬运动。然而，这些技术通常涉及有限数量的被跟踪个体，这使得任何对生存概率的稳健估计的统计能力都较低。此外，当使用地理定位器时，只有在个人重新捕获时才能访问数据，这带来了潜在的偏差来源。我们使用多事件建模，在分析迁徙海鸟 Calonectris diomedea 的 1104 个长期个体捕获历史 （2000-2022） 中包括 147 个已确定的越冬足迹的信息，然后测试个体对越冬区域的偏好是否可能驱动成年生存的异质性。我们还检查了个体对越冬地区的保真度，并测试了由 wNAO 和 SOI 气候指数表示的气候和海洋条件是否会影响生存率和保真度。对越冬区的保真度约为 0.79。区域之间的年变化受 wNAO 驱动的环境变异性的影响。生存概率受 SOI 影响，并且因越冬地区而异;这些差异加上高越冬地点保真度，产生了成虫存活率的个体异质性。我们的研究表明，在过去的二十年里，一些个体在不太适合的地区越冬，对成虫的生存产生了不可忽视的影响，而成虫的生存率是长寿物种中种群增长率最敏感的参数。冬季海洋条件，如暴风雨天气或靠近上升流，可能在推动生存异质性方面发挥相关作用。需要进一步的研究来增强我们对气候、局部选择压力和个体条件的相互关联影响如何影响迁徙物种种群动态的理解。
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