Seabirds as samplers of the marine environment – a case study in Northern Gannets
Stefan Garthe1, Verena Peschko1, Ulrike Kubetzki1,2, and Anna-Marie Corman11Research & Technology Centre (FTZ), Kiel University, Hafentörn 1, D-25761 Büsum, Germany 2Department of Animal Ecology and Conservation, Biocentre Grindel, Hamburg University, Martin-Luther-King Platz 3, 20146 Hamburg, Germany
Received: 29 Apr 2016 – Accepted for review: 26 May 2016 – Discussion started: 27 Jun 2016
Abstract. Understanding distribution patterns, activities, and foraging behaviours of seabirds requires interdisciplinary approaches. In this paper, we provide examples of the data and analytical procedures from a new study in the German Bight, North Sea, tracking Northern Gannets (Morus bassanus) at their breeding colony on the island of Helgoland. Individual adult Northern Gannets were equipped with different types of data loggers for several weeks, measuring geographic positions and other parameters mostly at 3–5 min intervals. Birds flew in all directions from the island to search for food, but most flights targeted areas to the (N)NW of Helgoland. Foraging trips were remarkably variable in duration and distance; most trips lasted 1–15 h and extended from 3–80 km from the breeding colony on Helgoland. Dives of gannets were generally shallow, with more than half of the dives only reaching depths of 1–3 m. The maximum dive depth was 11.4 m. Gannets showed a clear diurnal rhythm in their diving activity, with dives being almost completely restricted to the daylight period. Most flight activity at sea occurred at an altitude between the sea surface and 40 m. Gannets mostly stayed away from the wind farms and passed around them much more frequently than flying through them. Detailed information on individual animals may provide important insights into various processes, based on multi-layer information.
Garthe, S., Peschko, V., Kubetzki, U., and Corman, A.-M.: Seabirds as samplers of the marine environment – a case study in Northern Gannets, Ocean Sci. Discuss., doi:10.5194/os-2016-22, in review, 2016.