Despite its importance for ecology and conservation, we are still far from understanding how environmental variability interacts with intrinsic factors and individual specialization to determine trophic strategies of long-lived taxa, mostly due to difficulties in studying the same animals over extended periods. Here, by yearly consistently sampling the first primary feather of 99 Cory’s shearwaters (Calonectris borealis) foraging in the Canary Current (CC) upwelling ecosystem, we provide robust evidence on the individual changes of isotopic ratios of carbon (δ¹³C) and nitrogen (δ¹⁵N) over 17 years. We reported a slight longitudinal decline of δ¹³C values throughout 2001–2017, even after being adjusted for the marine Suess effect (linked to the increasing CO₂ emissions). Although CC is often considered to be overexploited by industrial fisheries, we could not detect a decline in Cory’s shearwater trophic level indicating a change in the trophic web structuring, as revealed by δ¹⁵N. We found negative correlations of δ¹³C and δ¹⁵N with the CC upwelling intensity, indicating annual variability in baseline isotopic levels propagates through the food chain and it integrates in predators’ tissues. Low individual repeatabilities among years at population level indicates low long-term specialization, suggesting long-lived individuals foraging on highly productive areas can adjust their foraging strategies and diet according to environmental variability. However, individual-level repeatabilities in isotopic values showed a range of individual specialization within the population, indicating most individuals are generalist and a few of them highly specialized. First, although we found a clear influence of the upwelling intensity on the trophic ecology of birds, we could not detect any temporal trend in the trophic level of the Cory’s shearwater population, suggesting a stability in the structure of the pelagic food web of the CC over the last two decades despite the fishing pressure. Second, the existence of individual specialization highlights the importance of considering the repeated sampling of individuals to detect small changes in the trophic ecology of a population. Finally, the coexistence of individuals with different degree of specialization (from extremely flexible [generalists] to highly consistent individuals [specialists]) within a population can have deep implications on the capacity of populations to cope with environmental change.

尽管它对生态和保护具有重要意义，但我们仍远未了解环境变异性如何与内在因素和个体专长相互作用来确定长寿类群的营养策略，这主要是由于难以长期研究同一动物。这里，通过每年持续采样的99个Cory的鹱（第一主羽毛Calonectris北极光）在加那利电流（CC）觅食涌生态系统中，我们提供在碳上的同位素比率的个体变化（δ有力的证据¹³ C）和氮（ δ ¹⁵ N）超过17年。我们报道δ略有下降纵向¹³即使在针对海洋Suess效应进行调整（与增加的CO ₂排放量相关联）之后，整个2001-2017年的C值也是如此。虽然CC通常被认为是工业渔业过度开发，我们没有发现在Cory的海鸥营养水平表明在营养网结构变化的下降，由δ所揭示¹⁵ N.我们发现δ负相关¹³ C和δ ¹⁵具有CC上升强度的N，表明基线同位素水平的年度变化通过食物链传播，并整合到捕食者的组织中。在人口水平上，年间个体重复性低表明长期专业化程度低，这表明在高产地区觅食的长寿个体可以根据环境变化来调整觅食策略和饮食。但是，同位素值中个体水平的可重复性显示了种群中个体的特定范围，这表明大多数个体是通才的，其中一些个体是高度特殊的。首先，尽管我们发现上升强度对鸟类的营养生态有明显影响，但我们无法检测到Cory剪切水种群的营养水平的任何时间趋势，这表明尽管有捕捞压力，但在过去的二十年中，CC的中上层食物网的结构是稳定的。其次，个体专业化的存在凸显了考虑对个体进行重复采样以检测种群营养生态的细微变化的重要性。最后，人口中具有不同专业化程度的个人（从极其灵活的[一般主义者]到高度一致的个人[专家]）的共存可能会对人口应对环境变化的能力产生深远的影响。个体专业化的存在凸显了考虑对个体进行重复采样以检测种群营养生态的细微变化的重要性。最后，人口中具有不同专业化程度的个人（从极其灵活的[一般主义者]到高度一致的个人[专家]）的共存可能会对人口应对环境变化的能力产生深远的影响。个体专业化的存在凸显了考虑对个体进行重复采样以检测种群营养生态的细微变化的重要性。最后，人口中具有不同专业化程度的个人（从极其灵活的[一般主义者]到高度一致的个人[专家]）的共存可能会对人口应对环境变化的能力产生深远的影响。