A large, thickset but elegant diving duck, seen in flocks on the sea, small numbers on freshwater.

Scaup may turn up in many different situations: in lively, buoyant flocks on choppy seas, on large rafts drifting sleepily on smooth, sheltered estuaries, or as isolated individuals among dense flocks of Tufted Ducks and Pochards on inland lakes. However most spend winter on traditional coastal feeding sites.