Lesser Scaup
Differentiating between Greater and Lesser Scaups is not easy, especially for females such as this one. The general rule in the boreal winter is that the Greater Scaup prefers saltwater and the Lesser fresh, but truth be told, the Lesser Scaup could be found on either fresh or salt. The Greater Scaup would have a broader head at this angle of view with a larger "nail", the black area on the front of the bill. When you are this close, the colour of the iris is a big help - amber in Lesser and bright yellow in Greater. The best way to tell them apart is to see them flying since the Greater Scaup has much more white in the wing. Hunters call these ducks "Bluebills" for obvious reasons. Dec 29, 2010.
Lesser Scaup
Differentiating between Greater and Lesser Scaups is not easy, especially for females such as this one. The general rule in the boreal winter is that the Greater Scaup prefers saltwater and the Lesser fresh, but truth be told, the Lesser Scaup could be found on either fresh or salt. The Greater Scaup would have a broader head at this angle of view with a larger "nail", the black area on the front of the bill. When you are this close, the colour of the iris is a big help - amber in Lesser and bright yellow in Greater. The best way to tell them apart is to see them flying since the Greater Scaup has much more white in the wing. Hunters call these ducks "Bluebills" for obvious reasons. Dec 29, 2010.