Abstract
In 2022, Ecowende was granted permission to build an offshore wind farm in the Dutch North Sea named Hollandse Kust West (HKW). This wind farm has groundbreaking mitigation goals relating to the ecological effects of wind farms and serves as a prime location for research to assess whether the ecological effects of future wind farms can be reduced. One of the knowledge gaps relating to the potential effects of operational wind farms on birds that was identified during the tender phase of HKW relates to great black backed gull collision and displacement. This is due to an absence of fundamental knowledge of great black-backed gull spatial and foraging ecology in the North Sea. Filling this knowledge gap by GPS-tracking individual birds is one of the projects that falls under the ecological research program of HKW. The study at hand forms the first year of this project, which will track great black-backed gulls over multiple years, both prior to and following construction of the wind farm. The GPS transmitters deployed during this first study year are performing well and are providing a wealth of spatial data. Thanks to these data, we have identified a core foraging area of the gulls breeding in our study area, information that may be useful for the wider protection of this declining species. Importantly, and in contrast to previous studies, we did not observe a negative effect of deployment of GPS transmitters on the gulls’ breeding performance; equal numbers of chicks fledged from nests where one of the parents was equipped with a GPS transmitter and from nests where no parent carried a GPS transmitter. With these promising first results, we are confident that we will collect reliable long-term data, as well as detailed, broad scale information about distribution, habitat choice and (foraging) behaviour of great black-backed gulls in the North Sea. Based on the data collected during the breeding period in 2024, two scientific articles will be prepared: one focusing on foraging preferences, and the second on flight heights.