LESSER SCAUP – (Aythya affinis)
The Lesser Scaup is a very abundant North American small diving duck, measuring some 45 cm (18 in.) long. The breeding male (drake) has a slightly iridescent black head, a black neck and breast, and rump. The back and wings are finely striated black on white, and the sides and belly are white. The eyes are yellow and the bill is light grey, with a tiny black tip. Females are brown overall, with a darker head and a white patch at the base of the bill, which is black. The wings are brown with a white band on the secondaries. Non-breeding males are brown overall, with the back and sides finely striated on light grey.
The English name ‘Lesser’ implies that there is a ‘Greater’ Scaup, which is very similar, and makes the two species difficult to distinguish. The name ‘Scaup’ would origin from Sottish ‘scalp’ and refers to a ledge in the water, where these ducks gather to feed. Another explanation would be that it is an onomatopoeia for one of the female’s calls. The Latin genus name ‘Aythya’ comes from Greek and refers to a ‘kind of waterbird’, and the species name ‘affinis’ means ‘related’, in reference to its similarity to the greater scaup.
The habitat of the lesser scaup includes wetlands such as marshes, ponds, small lakes, reservoirs, and coastal bays in the winter. They forage on the bottom in the mud for molluscs (including the invasive Zebra mussel), small crustaceans, plant material such as seeds, and insects and their larvae.
Lesser scaups build their nests in a sheltered area among thick vegetation near water, or on floating vegetation. These are social birds that congregate with other duck species. Sometimes flocks on the water are so dense as to form a floating ‘mat’.
The lesser scaup does not breed on PEI. Its occurrence on the island varies according to the seasons and the years, from uncommon to occasional to rare. In addition, it is a duck species with an ‘irruptive’ behavior. A few sightings at various locations have been reported in the fall of 2005, during migration.
Its main breeding range encompasses the Prairie Pothole region and the Canadian boreal forest up to the tundra. Lesser scaups migrate to the southern half of the USA for the winter, and also to Mexico, the Caribbean and Central America.
Conservation: the population of the lesser scaup has declined steadily over the last few decades, but the species is still listed as of ‘least concern’ due to its high numbers. Some potential threats include habitat degradation and loss due to oil spills or other form of pollution, resource extraction, and hunting (although legally hunted, the number of catches is limited.)