Inter-breeding movements of common guillemots (Uria aalge) suggest the Barents Sea is an important autumn staging and wintering area

Abstract

Seabird movements outside the breeding season are generally poorly known, but can cover thousands of square km and a multitude of habitats, feeding conditions and potential threats. During the last decades, many seabird species in the North Atlantic have experienced large reductions in population size and breeding success, probably caused by reduced prey abundance caused by climate alterations and overfishing. One of these seabird species is the common guillemot. We used global location sensors (geolocators) to identify inter-breeding movements of 10 individuals breeding at Sklinna, a colony off the coast of Central Norway during July 2009–July 2010. All individuals moved northwards after breeding, and eight of them (80 %) entered the Barents Sea where they probably completed their moult. Three individuals moved southwards before the winter, but in total, half of the individuals stayed in the Barents Sea during winter. The other half wintered off the coast of Central Norway–Lofoten. The fact that all individuals moved northwards to winter was surprising as ringing recoveries suggest they also moves southwards (to the Skagerrak area) to winter. This suggests variation (individual or annual) in wintering movements and calls for a multi-year geolocator study at a number of colonies. Much of the area in the Barents Sea–Lofoten area is classified as vulnerable with respect to specific environmental pressures such as oil pollution and other anthropogenic factors, and the importance of the Barents Sea as a major wintering area for common guillemots from central Norway certainly has implications for the management authorities.