Data from: Effects of age and reproductive status on individual foraging site fidelity in a long-lived marine predator

Individual foraging specializations, where individuals use a small component of the population niche width, are widespread in nature with important ecological and evolutionary implications. In long-lived animals, foraging ability develops with age, but we know little about the ontogeny of individuality in foraging. Here we use precision global positioning system (GPS) loggers to examine how individual foraging site fidelity (IFSF), a common component of foraging specialization, varies between breeders, failed breeders and immatures in a long-lived marine predator—the northern gannet Morus bassanus. Breeders (aged 5+) showed strong IFSF: they had similar routes and were faithful to distal points during successive trips. However, centrally placed immatures (aged 2–3) were far more exploratory and lacked route or foraging site fidelity. Failed breeders were intermediate: some with strong fidelity, others being more exploratory. Individual foraging specializations were previously thought to arise as a function of heritable phenotypic differences or via social transmission. Our results instead suggest a third alternative—in long-lived species foraging sites are learned during exploratory behaviours early in life, which become canalized with age and experience, and refined where possible—the exploration-refinement foraging hypothesis. We speculate similar patterns may be present in other long-lived species and moreover that long periods of immaturity may be a consequence of such memory-based individual foraging strategies.个体觅食特化（即个体仅利用种群生态位宽度中的一小部分资源）在自然界中广泛存在，且具有重要的生态学与进化学意义。对于长寿动物而言，其觅食能力会随年龄增长逐步发育，但学界对觅食行为中个体特化的个体发育过程仍知之甚少。本研究借助高精度全球定位系统（GPS）记录仪，以长寿海洋捕食者北方塘鹅（*Morus bassanus*）为研究对象，探究觅食特化的常见表征——个体觅食位点保真度（IFSF）在繁殖个体、繁殖失败个体与未成熟个体间的差异。5龄及以上的繁殖个体表现出极强的IFSF：它们在连续多次觅食航行中路线高度相似，且忠实于远端觅食位点。然而，2~3龄的未成熟个体探索性更强，既无固定航行路线，也缺乏觅食位点保真度。繁殖失败的个体则处于中间状态：部分个体具有较强的位点保真度，另一部分则更具探索性。此前学界普遍认为，个体觅食特化要么源于可遗传的表型差异，要么通过社会传播形成。本研究结果则提出了第三种备选机制：在长寿物种中，觅食位点是在生命早期的探索行为中习得的，随后随年龄增长与经验积累逐渐固化，并在可行范围内不断优化——这一假说被称为“探索-优化觅食假说（exploration-refinement foraging hypothesis）”。我们推测，类似的模式或许也存在于其他长寿物种中，且未成熟阶段的漫长周期，可能正是这种基于记忆的个体觅食策略所带来的结果。