Greater Scaup Aythya marila

Identification Tips:

• Length: 13 inches Wingspan: 31 inches
• Small, compact diving duck
• Rounded crown
• Yellow eyes (brown in immatures)
• Blue bill with black nail at tip
• Dark wing with dark-tipped white secondaries and inner primaries and pale gray outer primaries
• Immature female similar to adult female, immature male is similar to female in autumn, but acquires alternate plumage during winter

Adult male alternate:

• Alternate plumage worn from fall through early summer
• Glossy greenish head
• Black breast
• Whitish or pale gray flanks, white belly
• Whitish back with fine black vermiculations
• Black tail, upper- and under-tail coverts

Adult male basic:

• Similar to adult female

Adult female:

• Distinct white band around base of bill
• Dark brown body plumage
• Whitish belly

Similar species:

The Greater Scaup can be distinguished from the very similar Lesser Scaup by its larger size, wing stripe that extends well into the primaries, and glossy, greenish head as an adult male in alternate plumage. Adult male Ring-necked Duck similar in alternate plumage but has quite different bill pattern, black back, grayer flanks and vertical white finger just behind black breast. The Ring-necked Duck favors freshwater habitats while the Greater Scaup prefers brackish or saltwater habitats. Very rare Tufted Duck is similar but note the distinctive tuft at the rear of the head. When the tuft is not visible, adult males have black backs. Females are very similar but usually lack white band around base of bill and have more black at the tip of the bill. The female Redhead is very similar in shape and coloration to the female Greater Scaup but it lacks the white patch at the base of the bill and has a gray wing stripe.

Length and wingspan from: Robbins, C.S., Bruun, B., Zim, H.S., (1966). Birds of North America. New York: Western Publishing Company, Inc.

Above information used courtesy of United States Geological Survey.