- 15.4–22 in
- 28.3–31.1 in
- 25.6–48 oz
- Scaup (British English)
- Fuligule milouinan (French)
- Porron bastardo, Buixot (Spanish)
- Occasionally an older female Greater Scaup will have male-like head color and male patterning on her back, but she still has the typical white face patch of a female.
- Once incubation begins, the male Greater Scaup leaves the female and goes to molt on some relatively large, isolated lake. These lakes are used year after year during molt, and may be in the immediate vicinity of the breeding wetlands or many miles away. They are relatively shallow and contain abundant food and suitable cover.
- The nest of a Greater Scaup is usually lined with a thick layer of down plucked by the mother from her own breast. Nests of poor-condition females may lack down and instead may contain small, grayish-white feathers plucked from beneath the outer body feathers.
- The oldest recorded Greater Scaup was a male, and at least 20 years, 5 months old when he was found in Michigan in 2007. He had been banded in New York in 1998.
Found on lakes, ponds, and bays. Mostly marine in winter.
Clams, snails, crustaceans, aquatic insects, seeds, and aquatic plants.
- Clutch Size
- 5–13 eggs
- Egg Description
- Brownish olive-buff.
- Condition at Hatching
- Downy and eyes open. Leave nest as soon as they are dry. Feed themselves immediately.
Bowl-shaped depression in ground, usually lined with grasses and a thick layer of down. Placed in tall grass in an area not subject to flooding.
Dives under water to capture food.
Greater Scaup numbers appear to have declined since the 1950's according to the U.S. Fish & Wildlife Service. However, population trends are difficult to estimate, in part because of similarities to abundant Lesser Scaup, making accurate winter counts difficult to obtain. The 2014 State of the Birds lists Greater Scaup as a Common Bird in Steep Decline.
- Kessel, B., D. A. Rocque, and J. S. Barclay. 2002. Greater Scaup (Aythya marila). In The Birds of North America, No. 650 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA
- North American Bird Conservation Initiative, U.S. Committee. 2014. State of the Birds 2014 Report. U.S. Department of Interior, Washington, DC.
- U.S. Fish and Wildlife Service. 2015. Waterfowl Population Status, 2015. U.S. Department of the Interior, Washington, DC.
- USGS Patuxent Wildlife Research Center. 2015. Longevity records of North American Birds.