Terrestrial and Marine Foraging Strategies of an Opportunistic Seabird Species Breeding in the Wadden Sea

Lesser black-backed gulls, often considered primarily pelagic, exhibit significant terrestrial foraging behavior during the breeding season in the Wadden Sea. This study reveals that these gulls make intensive use of both marine and inland landscapes, with foraging trips varying from 0.5 to 26.4 hours and covering distances up to 333.6 km. While they foraged predominantly on bare ground, particularly in potato fields, their diet included a mix of grass, insects, fish, litter, and earthworms. Marine foraging trips were more variable and often occurred at night, overlapping with fishing vessel activities, whereas inland trips were closely tied to daylight hours. The study used GPS data loggers attached to incubating birds to track flight paths and analyze habitat use, diet, and isotopic signatures in blood, providing a comprehensive understanding of their opportunistic foraging strategies.

Garthe, S., Schwemmer, P., Paiva, V. H., Corman, A.-M., Fock, H. O., Voigt, C. C., & Adler, S. (2016). Terrestrial and Marine Foraging Strategies of an Opportunistic Seabird Species Breeding in the Wadden Sea. Plos One, 11(8), e0159630. https://doi.org/10.1371/journal.pone.0159630