O_BALGZAND - Eurasian oystercatchers (Haematopus ostralegus, Haematopodidae) wintering on Balgzand (the Netherlands) is a bird tracking dataset published by Sovon, the University of Amsterdam and the Research Institute for Nature and Forest (INBO). It contains animal tracking data collected during CHIRP (Cumulative Human Impact on biRd Populations) for the study O_BALGZAND using trackers developed by the University of Amsterdam Bird Tracking System (UvA-BiTS, http://www.uva-bits.nl). The study was operational from 2010 to 2014. In total 22 individuals of Eurasian oystercatchers (Haematopus ostralegus) have been tagged while overwintering in the Balgzand area in the Western Wadden Sea (the Netherlands), mainly to study how they utilize intertidal flats in relation to food availability in winter. 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 van der Kolk et al. (2022, ... : This version adds alt-project-id to the reference-data and references the latest Movebank Attribute Dictionary. ...