Intercolony variations in movement patterns and foraging behaviors among herring gulls ( Larus argentatus ) breeding in the eastern Wadden Sea

Herring gulls (Larus argentatus) breeding in the eastern Wadden Sea exhibit significant intercolony variations in foraging behavior, with those on islands farther from the mainland relying more on local tidal flats for food, while those closer to the mainland venture farther, including terrestrial habitats. Gulls on distant islands primarily feed on common cockles and shore crabs near their colonies, whereas those nearer to the mainland forage extensively on neobiotic razor clams in intertidal zones and earthworms on the mainland. This shift is driven by reduced prey availability close to breeding sites, forcing gulls to adapt their foraging strategies. The study used GPS data loggers (1,115 trips from 37 individuals) and stable isotope analysis to reveal these patterns, highlighting herring gulls as indicators of intertidal ecosystem health.

Enners, L., Schwemmer, P., Corman, A.-M., Voigt, C. C., & Garthe, S. (2018). Intercolony variations in movement patterns and foraging behaviors among herring gulls ( Larus argentatus ) breeding in the eastern Wadden Sea. Ecology and Evolution, 8(15), 7529–7542. Portico. https://doi.org/10.1002/ece3.4167