Greater scaup days. The down-covered ducklings are able to follow their mother in her search for food immediately after hatching. Greater scaup eat aquatic molluscs, plants, and insects, which they obtain by diving underwater. They form large groups, called "rafts", that can number in the thousands. Their main threat is human development, although they are preyed upon by owls, skunks, raccoons, foxes, coyotes, and humans. Greater scaup populations have been declining since the 1980s; however, they are still listed as a species of least concern on the IUCN Red List. The genus name "Aythya" is derived from the Ancient Greek "aithuia" which
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