Data for: Early-life behavior predicts first-year survival in a long-distance avian migrant

Early-life conditions have critical, long-lasting effects on the fate of individuals, yet early-life activity has rarely been linked to subsequent survival of animals in the wild. Using high-resolution GPS and body-acceleration data of 93 juvenile white storks (Ciconia ciconia), we examined the links between behavior during both pre-fledging and post-fledging (fledging-to-migration) periods and subsequent first year survival. Juvenile daily activity (based on overall dynamic body acceleration) showed repeatable between-individual variation, the juveniles’ pre and post-fledging activity levels were correlated, and both were positively associated with subsequent survival. Daily activity increased gradually throughout the post-fledging period, and the relationship between post-fledging activity and survival was stronger in individuals who increased their daily activity level faster (an interaction effect). We suggest that high activity profiles signified individuals with increased pre-migratory experience, higher individual quality and perhaps more proactive personality, which could underlie their superior survival rates. The duration of individuals’ fledging-to-migration periods had a hump-shaped relationship with survival: higher survival was associated with intermediate rather than short or long durations. Short durations reflect lower pre-migratory experience, whereas very long ones were associated with slower increases in daily activity level which possibly reflects slow behavioral development. In accordance with previous studies, heavier nestlings and those that hatched and migrated earlier had increased survival. Using extensive tracking data, our study exposed new links between early-life attributes and survival, suggesting that early activity profiles in migrating birds can explain variation in first-year survival.

Methods
GPS-body acceleration data from tramsitteres that were fitted to white storks as nestlings and cover the pre-/post-fledging periods. Data were proccessed in Matlab R 2016.

生命早期环境对个体命运具有关键且持久的影响，但目前鲜有研究将动物生命早期的活动水平与野外后续存活率建立关联。本研究借助93只幼年白鹳（Ciconia ciconia）的高分辨率全球定位系统（GPS）和身体加速度数据，分析了离巢前与离巢后（离巢至迁徙阶段）的行为与个体后续第一年存活率之间的关联。基于整体动态身体加速度计算得到的幼鸟每日活动水平存在个体间可重复的差异；幼鸟离巢前与离巢后的活动水平呈显著相关，且二者均与后续存活率呈正相关。在离巢后阶段，幼鸟的每日活动水平随时间逐渐升高；且在每日活动水平提升更快的个体中，离巢后活动与存活率的关联强度更强（交互效应）。本研究推测，较高的活动特征预示着个体具备更丰富的迁徙前经验、更优异的个体素质，或拥有更主动的人格特质，这些因素或可解释其更高的存活率。个体离巢至迁徙的持续时长与存活率呈驼峰型关联：存活率较高的个体，其离巢至迁徙的时长处于中等水平，而非过短或过长。时长过短意味着个体迁徙前经验不足，而时长过长则与每日活动水平提升较慢相关，这可能反映出个体行为发育迟缓。与既往研究结果一致，体重较大的雏鸟以及孵化和迁徙时间更早的个体存活率更高。本研究借助大规模追踪数据，揭示了生命早期特征与存活率之间的全新关联，表明迁徙鸟类的生命早期活动特征可以解释其第一年存活率的个体差异。

研究方法
本研究使用的GPS-身体加速度数据来自雏鸟阶段佩戴于白鹳身上的追踪发射器，数据覆盖离巢前与离巢后阶段。所有数据均通过Matlab R 2016软件进行处理。