The lesser scaup (Aythya affinis) is a small North American diving duck that migrates south as far as Central America in winter. It is colloquially known as the little bluebill or broadbill because of its distinctive blue bill. The origin of the name scaup may stem from the bird's preference for feeding on scalp—the Scottish word for clams, oysters, and mussels; however, some credit it to the female's discordant scaup call as the name's source.

Description

Adults are long, on average. The species can weigh ; males weigh on average while females weigh noticeably less, at on average. and that of immatures is brown. Downy hatchlings look much like those of related species, with dark brown upperparts and pale buff underparts, chin, supercilium and back spots. In flight, the most tell-tale sign is the white secondary remiges, whereas in the greater scaup the white extends on the primary remiges also, i.e. far towards the wingtip. The specimens were collected in North America and came to the Liverpool national collection via Thomas Campbell Eyton's collection and the 13th Earl of Derby's collection which was bequeathed to the people of Liverpool in 1851. The clutch numbers about 9–11 eggs on average; up to 26 eggs have been found in a single nest, but such high numbers are from more than one female. Incubation is by the female only and lasts around 3 weeks. The young fledge some 45–50 days after hatching and soon thereafter the birds migrate to winter quarters already. Lesser scaup become sexually mature in their first or second summer. The oldest known individual reached an age of over 18 years.

Further reading

  • Farrand, John Jr. & National Audubon Society (1983): The Audubon Society master guide to birding. Alfred A. Knopf, New York.
  • Svensson, Lars; Zetterström, Dan; Mullarney, Killian & Grant, P. J. (1999): Collins bird guide. Harper & Collins, London.
  • Lesser Scaup - Aythya affinis - USGS Patuxent Bird Identification InfoCenter
  • The Nature Conservancy's Species profile for the Lesser Scaup