This is a dataset generated from information extracted from previously published studies, for the purpose of a meta-analysis investigating fitness benefits of different migratory strategies in partially migratory populations. Each line of data includes a mean and associated variance for a given fitness metric for both migrants and residents extracted from a study, in addition to information concerning population location, study species, type of fitness metric, year data were collected, and details on the publication from which the data were obtained. Data were collected as part of a NERC-funded PhD project, grant number NE/L002582/1. Full details about this dataset can be found at https://doi.org/10.5285/1a4e8d59-e112-4de6-a06b-9ea47ff15815
