Summer fieldwork! Tracking Lesser Black-backed Gull Foraging in the North Sea

This summer marked an exciting milestone in my PhD research, with the successful deployment of the first 10 tracking tags on adult lesser black-backed gulls (Larus fuscus) breeding on Vlieland. I am Simon Niessen, a PhD candidate at IBED and part of the NO-REGRETS consortium. Under the supervision of Prof. Dr. Judy Shamoun-Baranes (University of Amsterdam), Dr. Eldar Rakhimberdiev (University of Amsterdam), and Dr. Rosemarie Kentie (NIOZ), I study the foraging ecology of seabirds in the North Sea. My research explores how environmental conditions influence where and when seabirds forage, generating ecological knowledge that can support assessments of potential impacts from future offshore developments, including offshore wind farms.

To answer these questions, I use visual observations of seabird behaviour collected during the NO-REGRETS research cruises, and GPS and accelerometry tracking data of lesser black-backed gulls from breeding colonies in IJmuiden, Schiermonnikoog and Texel (UvA-BiTS, 2008–2026). As part of this work, we are expanding the long-term UvA-BiTS tracking dataset with 20 new Ornitela tag deployments on adult lesser black-backed gulls breeding in Vlieland. This new colony improves coverage of seabird foraging movements in the North Sea, particularly around the Frisian Front, an ecologically important and seasonally productive foraging area.

The first 10 Ornitela tracking tags have now been successfully deployed on June 6^th by Dr. Kees Camphuysen (NIOZ) and Peter de Boer (Sovon Vogelonderzoek Nederland). By combining movement and accelerometry data, I aim to classify different foraging strategies and quantify the environmental conditions that drive them.

The first tracking data from these new deployments already show a diverse range of movements, including some trips extending far offshore into and beyond the Frisian Front Natura 2000 area. The new deployments are an important addition to the long-term dataset and will help us better understand how seabirds use the North Sea in a rapidly changing marine environment.

Below are two examples of these offshore movements, where GPS fixes are coloured according to flight speed (km/h).  The GPS fixes were recorded at intervals ranging from 30 seconds to 5 minutes, with the vast majority collected at 30-second intervals. The trip on the left (KFFJ) lasted 35.4 hours and covered 326 km (23–24 June), while the trip on the right (KFFL) lasted 6.8 hours and covered 220.9 km (26 June).