Greater scaup Greater scaup The greater scaup ("Aythya marila"), just scaup in Europe or, colloquially, "bluebill" in North America, is a mid-sized diving duck, larger than the closely related lesser scaup. It spends the summer months breeding in Alaska, northern Canada, Siberia, and the northernmost reaches of Europe. During the winter, it migrates south to the coasts of North America, Europe, and Japan. Drake greater scaup are larger and have more rounded heads than the females; they have a bright blue bill and yellow eyes. Their heads are dark, with a green gloss; the breast is black, the belly white and the
Lesser scaup alone. The nest is a shallow depression scraped in the ground and lined with plants and some down feathers. Breeding begins in May, but most birds nest only in June, later than usual for North American waterfowl. 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