Seabirds at sea, November 1991 – February 1992

Most ship-based surveys were on board of MV Navicula and all were organised by Netherlands Institute for Sea Research (NIOZ, MFL). The Navicula surveyed a narrow strip along the Dutch and German coastline, in an attempt to find the major concentrations of seaduck and divers in these waters. Large numbers of Redthroated divers were found in German waters, mainly between the mouth of the River Elbe and the isle of Sylt. Some groups appoached the number of 100 birds in this area. Off the west-Frisian islands, west of the river Elbe the numbers were generally lower, with the birds being concentrated in the shallow areas between islands. Along the Dutch mainland coast, numbers of divers were lower again, off the Dutch Delta area another small concentration was found. In this last area, off Walcheren, also high numbers of Great Crested Grebes were found at sea. Some very large concentrations of Common Scoters were found off the Dutch Wadden isles, generally at the same locations as last year. The largest group, estimated at ca. 75.000 was found at Terschelling, and another 50,000 at Schiermonnikoog. Numbers of Eiders in the North Sea were much larger than last year. North of the Dutch Wadden Sea, tens of thousands were found, concentrating in the same areas as the seaduck. Thousands of Eiders were also found along the Dutch mainland coast, and a new wintering location seemed established in the Delta area, with some 10.000 near the former island Goeree. The exodus from the Wadden Sea is obviously caused by acute food shortages due to the shellfish fisheries in the Wadden Sea. Seabirds that are normally more pelagically orientated, were remarkebly absent in the coastal area this winter. Numbers of auks, fulmars and kittiwakes all were very low. More surprisingly, also Little Gulls were nearly absent in these waters this winter. Common Gulls on the other hand, were found in very high numbers in the German Bight, as this is their main wintering area in the North Sea.