LBBG_JUVENILE - Juvenile lesser black-backed gulls (Larus fuscus, Laridae) and herring gulls (Larus argentatus, Laridae) hatched in Zeebrugge (Belgium) is a bird tracking dataset published by the Research Institute for Nature and Forest (INBO) . It contains animal tracking data collected by the LifeWatch GPS tracking network for large birds ( http://lifewatch.be/en/gps-tracking-network-large-birds ) for the project/study LBBG_JUVENILE , using trackers developed by Ornitela ( https://www.ornitela.com ). The study has been operational since 2020. In total 92 individuals of lesser black-backed gull ( Larus fuscus ) and European herring gull ( Larus argentatus ) have been tagged shortly after fledging in the colony of Zeebrugge, mainly to study their habitat use and migration behaviour. Data are automatically synced with Movebank and from there periodically archived on Zenodo (see https://github.com/inbo/bird-tracking ). Files Data in this package are exported from Movebank study 1259686571 . Fields in the data follow the Movebank Attribute Dictionary and are described in <code>datapackage.json</code>. Files are structured as a Frictionless Data Package . You can access all data in R via <code>https://zenodo.org/records/12623345/files/datapackage.json</code> using frictionless . datapackage.json : technical description of the data files. LBBG_JUVENILE-reference-data.csv : reference data about the animals, tags and deployments. LBBG_JUVENILE-gps-yyyy.csv.gz : GPS data recorded by the tags, grouped by year. Acknowledgements This dataset was collected using infrastructure provided by INBO and funded by Research Foundation - Flanders (FWO) as part of the Belgian contribution to LifeWatch. ; This version adds data from 2023, updates the title, description and <code>study-name</code> to mention Larus argentatus , and references the latest Movebank Attribute Dictionary.