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, ...