Ugland, Cassandra R.Acker, PaulBurthe, Sarah J.Fortuna, RitaGunn, CarrieHaaland, Thomas R.Harris, Michael P.Morley, Timothy I.Newell, Mark A.Swann, Robert L.Wanless, SarahDaunt, FrancisReid, Jane2024-10-172024-10-172024-10Ugland, C R, Acker, P, Burthe, S J, Fortuna, R, Gunn, C, Haaland, T R, Harris, M P, Morley, T I, Newell, M A, Swann, R L, Wanless, S, Daunt, F & Reid, J 2024, 'Early-life variation in migration is subject to strong fluctuating survival selection in a partially migratory bird', Journal of Animal Ecology, vol. 93, no. 10, pp. 1567-1581. https://doi.org/10.1111/1365-2656.141720021-8790https://hdl.handle.net/2164/24431Open access via the Royal Society agreement We thank everyone who contributed to long-term field data collection, particularly Raymond Duncan, Sarah Fenn, Hannah Grist, Carl Mitchell, Calum Scott, Jenny Sturgeon, Moray Souter, John Anderson, and Harry Bell; NatureScot for allowing work on the Isle of May National Nature Reserve, and Isle of May Bird Observatory Trust for supporting the long-term ringing; and Suzanne Bonamour and Kenneth Aase for helpful discussions1510470101engadaptive phenotypic plasticity,cohortEuropean shag Gulosus aristotelisfluctuating selectionjuvenile survivalmulti-state capture-mark-recapturepartial seasonal migrationviabilityselectionQH301 BiologySupplementary Informationhttps://besjournals.onlinelibrary.wiley.com/action/downloadSupplement?doi=10.1111%2F1365-2656.14172&file=jane14172-sup-0001-Supinfo.docxQH301Journal article10.1111/1365-2656.14172http://www.scopus.com/inward/record.url?scp=85202822854&partnerID=8YFLogxK9310