Lesser Scaup

Aythya affinis

Order

ANSERIFORMES

Family

Ducks, Geese and Swans (Anatidae)

Code 4

LESC

Code 6

AYTAFF

ITIS

Egg Color:

Olive or olive buff.



Number of Eggs:

6 - 15



Incubation Days:

21 - 28



Egg Incubator:

Female



Nest Location:

In tall prairie grass.



Nest Material:

Grass lined with down.



Migration:

Migratory



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General

Lesser Scaup: Medium-sized diving duck with finely barred gray back and gray-washed white underparts. Head, neck and breast are black with purple gloss; blue-gray bill; black wings with large white patches; tail is black. Female is brown overall with white belly, wing patches and base of bill. Juvenile resembles female but duller with plain scapulars, paler brown underparts; white on face that is less defined. Young males have yellow eyes; females' eyes are brown or gray-olive. Non-breeding adults are duller than breeding adults.

Range and Habitat

Lesser Scaup: Breeds from interior Alaska and northern Canada south to Colorado, Nebraska, and occasionally farther east. Winters along coasts south from British Columbia and Massachusetts to Gulf of Mexico; also inland south of Colorado and the Great Lakes. Prefers ponds and marshes; during migration and winter is found on lakes, rivers, and ponds, and in the southern states on saltwater.

Breeding and Nesting

Lesser Scaup: Breeding occurs in May and June. Six to fifteen olive or olive buff eggs are laid in a down-lined cup of grass hidden in vegetation, often located some distance from water. Incubation ranges from 21 to 28 days, and is carried out by the female. The young leave the nest within a day of hatching and head to the water, where they are tended by the female but feed themselves.

Foraging and Feeding

Lesser Scaup: These ducks eat mainly aquatic invertebrates such as insects, crustaceans, mollusks and small fish. Seeds and vegetative parts of aquatic plants are important in certain areas. They feed primarily by diving. Foraging bouts are generally short and spread over an entire 24 hour period. These ducks can locate and pursue prey in the water column visually or feed tactilely.

Vocalization

Lesser Scaup: Although seldom heard, makes sharp whistles and guttural scolding notes.

Similar Species

Lesser Scaup: Greater Scaup is larger and has white wing stripe that extends through the secondaries onto the primaries; male has whiter sides and a more rounded head.

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UnderpartsX

Belly, undertail coverts, chest, flanks, and foreneck.

BellyX
The ventral part of the bird, or the area between the flanks on each side and the crissum and breast. Flight muscles are located between the belly and the breast.
BreastX
The upper front part of a bird.
FaceX
The front part of the head consisting of the bill, eyes, cheeks and chin.
ScapularsX
Short feathers in the area where the bird’s back and wings join.
Parts of a Standing bird X
Head Feathers and Markings X
Parts of a Flying bird X