Abstract
In each of the three years 2010-2012, adult northern gannets (Morus bassanus) from Bempton Cliffs, on the northeast coast of England, were fitted with satellite tags to investigate their foraging ranges during chick-rearing and early post-breeding periods. This was done to establish whether there is overlap with potential development zones for offshore wind energy generation in the North Sea. The three seasons of study, in 2010 (n=14 birds), 2011 (n=13) and 2012 (n=15), have identified the previously unknown sea areas used by adult gannets from Bempton Cliffs. Locations of tagged birds during chick-rearing coincided with the Hornsea offshore wind energy zone in particular, with some birds recorded on Dogger Bank and a few records in the East Anglia zone, and within the Greater Wash strategic area for offshore wind energy generation. Post-breeding locations overlapped with the Hornsea, Dogger Bank, and East Anglia zones before dispersal out of the North Sea or cessation of recording. This report presents comparative results for all three chick-rearing and, for a reduced sample of birds, early post-breeding periods. Breeding success at Bempton Cliffs was high in all three years. Locations during the three chick-rearing periods show a marked similarity in the area of active use, but a notable difference in the extent of the core area used in 2012. Distance to colony had the over-riding influence on foraging range. Relatively small annual samples mean that we remain unsure how representative the data are of year to year foraging activity by breeding gannets from Bempton Cliffs, especially in years of lower breeding productivity. However, the collective foraging range of the forty two tagged birds encompassed the full seaward radius around Bempton Cliffs, so we are reasonably confident that our results represent the sea areas used by adult gannets, at least in seasons of good breeding productivity.