Wetenschappelijk artikelTracking of Black-legged Kittiwakes from an offshore platform in the Dutch North Sea during summer

Black-legged Kittiwakes Rissa tridactyla (hereafter ‘Kittiwakes’) have increasingly been breeding on anthropogenic structures, including offshore platforms. Breeding on offshore platforms may result in smaller foraging ranges compared to natural breeding sites due to closer proximity to feeding areas and/or reduced competition at sea in comparison to mainland, coastal colonies of the same size, due to the greater access to sea area. We GPS-tracked nine Kittiwakes breeding on an offshore platform in the Dutch North Sea and compared movements between estimated breeding stages. Focusing on the early chick-rearing period, analysis of foraging ranges found in literature suggested shorter foraging ranges in colonies with greater access to sea area, and that foraging ranges of Kittiwakes breeding on platform L7- B were shorter than expected for a similarly sized coastal colony. Maximum trip distance increased during the estimated late chick-rearing and post-fledging periods and decreased again from mid-August to late September (post-breeding) with more time spent in the colony after which the birds did not return to the platform. During the entire study period, but most frequently in September, Kittiwakes visited one to seven other platforms, including platforms previously documented to host breeding Kittiwakes, suggesting prospecting behaviour. Remaining major knowledge gaps are the number of Kittiwakes breeding on platforms in the (Dutch) North Sea and their role in the meta-population dynamics of the North Sea population.