A general theory of avian migratory connectivity

• Published in: Ecology letters 2021-09, Vol.24 (9), p.1848-1858
• Main Authors: Somveille, Marius, Bay, Rachael A., Smith, Thomas B., Marra, Peter P., Ruegg, Kristen C., Storch, David
• Format: Article
• Language: English
• Subjects: 60 APPLIED LIFE SCIENCES; avian; Bird migration; Breeding; Connectivity; cost of migration; eBird; Energy expenditure; Environmental changes; genoscape; ideal free distribution; Impact prediction; migration; migratory; Migratory birds; Migratory connectivity; Migratory species; optimal migration; Overwintering behavior; Population dynamics
• ISSN: 1461-023X; 1461-0248
• DOI: 10.1111/ele.13817

Birds exhibit a remarkable array of seasonal migrations. Despite much research describing migratory behaviour, the underlying forces driving how a species’ breeding and wintering populations redistribute each year, that is, migratory connectivity, remain largely unknown. Here, we test the hypothesis that birds migrate in a way that minimises energy expenditure while considering intraspecific competition for energy acquisition, by developing a modelling framework that simulates an optimal redistribution of individuals between breeding and wintering areas. Using 25 species across the Americas, we find that the model accurately predicts empirical migration patterns, and thus offers a general explanation for migratory connectivity based on first ecological and energetic principles. Our model provides a strong basis for exploring additional processes underlying the ecology and evolution of migration, but also a framework for predicting how migration impacts local adaptation across seasons and how environmental change may affect population dynamics in migratory species. Despite much research describing migratory behaviour, the underlying forces driving how a species’ breeding and wintering populations redistribute each year, that is, migratory connectivity, remain largely unknown. Here, we test the hypothesis that birds migrate in a way that minimises energy expenditure while considering intraspecific competition for energy acquisition, by developing a modelling framework that simulates an optimal redistribution of individuals between breeding and wintering areas. Using empirical data for 7145 individuals from 25 species across the Americas, we find that the model accurately predicts empirical migration patterns, and thus offers a general explanation for migratory connectivity based on first ecological and energetic principles.