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 Central America, the West Indies and Bermuda. Wintering lesser scaup are typically found in freshwater or slightly brackish habitat and unlike greater scaup rarely are seen offshore when unfrozen freshwater habitat is available. They may even spend the winter on lakes in parks, as long as they are not harassed, and will occur even on smallish Caribbean islands such as Grand Cayman. Thousands winter each year on the Topolobampo lagoons in Mexico, and even in the southernmost major wintering location—Ciénaga Grande de Santa Marta in Colombia—hundreds of birds can be seen. In Central America, flocks are present from July on,