The " Lesser Scaup " problem

observations in Britain of ducks that were thought to be Lesser Scaups (Aythya affinis), a North American species not recorded in Europe. This note is based on a detailed examination of one of these --that first seen at Sutton Courtenay, Berkshire, in December 1957 and subsequently watched by a very large number of observers. This bird was present for three to four months in each of the winters 19...