Het tellen van Zwarte Zeeëenden Melanitta nigra voor de Nederlandse kust

A ship-based method for counting Common Scoters Melanitta nigra in Dutch coastal waters is suggested. By sailing through the centre of a group of ducks, this group will be forced to fly away from the ship. In Dutch coastal waters, the ducks strongly prefer to fly parallel to the coast and avoid the deeper offshore waters as well as the land. Groups forced to leave their preferred area will settle at sea again near their original spot. After the whole group has been ushered away repeatedly, at a certain moment the ducks will decide to brave the ship and fly back to their preferred area. Normally, the whole group (up to tens of thousands) will fly past, and can be counted with little chance for errors. With a dedicated ship that could sail in shallow waters, this method worked very well.