This project, part of our long-term study on Cory’s shearwaters Calonectris borealis on Selvagem Grande, looks at the causes and consequences of individual variability in the migratory strategies of a pelagic seabird, with relevance for marine monitoring in a context of global changes. Many hundred migratory journeys have been tracked using geolocators, making this one of the most comprehensive studies on bird migration worldwide.