Ontogenetic niche shifts have helped to understand population dynamics. Here we show that ontogenetic niche shifts also offer an explanation, complementary to traditional concepts, as to why certain species show seasonal migration. We describe how demographic processes (survival, reproduction and migration) and associated ecological requirements of species may change with ontogenetic stage (juvenile, adult) and across the migratory range (breeding, non-breeding). We apply this concept to widely different species (dark-bellied brent geese (Branta b. bernicla), humpback whales (Megaptera novaeangliae) and migratory Pacific salmon (Oncorhynchus gorbuscha) to check the generality of this hypothesis. Consistent with the idea that ontogenetic niche shifts are an important driver of seasonal migration, we find that growth and survival of juvenile life stages profit most from ecological conditions that are specific to breeding areas. We suggest that matrix population modelling techniques are promising to detect the importance of the ontogenetic niche shifts in maintaining migratory strategies. As a proof of concept, we applied a first analysis to resident, partial migratory and fully migratory populations of barnacle geese (Branta leucopsis). We argue that recognition of the costs and benefits of migration, and how these vary with life stages, is important to understand and conserve migration under global environmental change.

个体发育的利基转变有助于了解人口动态。在这里，我们表明，个体遗传学的生态位转移也为某些物种为何表现出季节性迁徙提供了一种解释，以补充传统观念。我们描述了人口的过程（生存，繁殖和迁移）以及相关的物种生态要求如何随个体发育阶段（幼年，成年）以及整个迁徙范围（繁殖，非繁殖）而变化。我们将此概念应用于广泛不同的物种（黑腹雁（Branta b。bernicla），座头鲸（Megaptera novaeangliae）和迁徙的太平洋鲑鱼（Oncorhynchus gorbuscha）以检查该假设的一般性。与个体生态位转移是季节性迁徙的重要驱动力这一观点相一致，我们发现，幼年生命阶段的生长和生存受益于繁殖地区特有的生态条件。我们建议矩阵人口建模技术有望在维持迁徙策略中检测个体发育的生态位转变的重要性。作为概念的证明，我们对藤壶鹅（Branta leucopsis）的常住，部分迁徙和完全迁徙种群进行了首次分析。我们认为，认识到迁移的成本和收益，以及它们随着生命阶段的变化，对于理解和保护全球环境变化下的迁移非常重要。