H_GRONINGEN - Western marsh harriers (Circus aeruginosus, Accipitridae) breeding in Groningen (the Netherlands) is a bird tracking dataset collected by the Grauwe kiekendief - Kenniscentrum Akkervogels (GKA) / Dutch Montagu’s Harrier Foundation and published by the Research Institute for Nature and Forest (INBO). It contains animal tracking data collected for the project/study H_GRONINGEN, using trackers developed by the University of Amsterdam Bird Tracking System (UvA-BiTS, http://www.uva-bits.nl). The study was operational from 2012 until 2018. In total 4 individuals of western marsh harriers (Circus aeruginosus) have been tagged in their breeding area in the province Groningen (the Netherlands) close to the Netherlands-Germany border, mainly to study their habitat use and migration behaviour. Data are uploaded from the UvA-BiTS database to Movebank and from there archived on Zenodo (see https://github.com/inbo/bird-tracking). No new data are expected. See Milotic et al. (2020, https://doi.org/10.3897/zookeys.947.52570) for a more detailed description of this dataset. Data in this package are exported from Movebank study H_GRONINGEN - Western marsh harriers (Circus aeruginosus, Accipitridae) breeding in Groningen (the Netherlands) (Movebank Study ID 922263102), which can be viewed at https://www.movebank.org/cms/webapp?gwt_fragment=page=studies,path=study922263102. Fields in the data follow the Movebank Attribute Dictionary (http://vocab.nerc.ac.uk/collection/MVB) and are described in datapackage.json. Files Files are structured as a Frictionless Data Package. You can access all data in R via https://zenodo.org/record/6574736/files/datapackage.json using frictionless. datapackage.json: technical description of the data files. H_GRONINGEN-reference-data.csv: reference data about the animals, tags and deployments. H_GRONINGEN-gps-yyyy.csv.gz: GPS data recorded by the tags, grouped by year. H_GRONINGEN-acceleration-yyyy.csv.gz: acceleration data recorded by the tags, grouped by year.