Here the classic head shape and color are very evident along with the large bill. When the lighting is just right, Greater Scaup can show a purple gloss and even Lesser can exhibit a greenish gloss but keep watching and you can detect the usual head color. Structural differences should separate the two species at such times. The sides are usually whiter on Greater and also note how much finer the markings are on the mantle compared to the courser markings on Lesser Scaup males.