Dataset: Plastic ingestion and diet composition in European shags (Gulosus aristotelis)

This dataset contains pellet-level data on prey composition and plastic debris (microfibers and other items) in European shags (Gulosus aristotelis) collected in northern Spain between 2006 and 2022. The dataset includes detailed counts of prey items by family, microfiber abundance by colour, and other ingested materials. R scripts used for statistical analyses and figure generation are also provided. This dataset supports a manuscript currently in press in Marine Pollution Bulletin, which will be linked to this repository upon publication.