Species

Greater scaup

Aythya marila

A diving duck of open bays and big lakes, very like the lesser scaup but rounder-headed and more coastal.

Photo Chuck Homler d/b/a Focus On Wildlife (opens in a new tab) / Wikimedia Commons, CC BY-SA 4.0 (opens in a new tab)

At a glance

Size: About 39 to 56 cm long
Weight: About 700 to 1,400 g
Habitat: Coastal bays, sounds and large reservoirs in winter
Diet: Clams, mussels, snails and aquatic plants
In Georgia: An uncommon winter visitor, mostly on the coast
Voice: Mostly quiet; a low "scaup" from females
Rabies vector: No

Identification

Male: Rounded head with a green gloss; black breast; pale grey back; white sides; blue bill with a broad black tip
Female: Brown with a broad white patch at the base of the bill
In flight: A long white stripe that runs well into the outer wing
Told apart from: Lesser scaup, which has a peaked head, a purple gloss and a shorter white wing stripe
Told apart from: Ring-necked duck, which has a black back and a white-ringed bill
Where to look: Rafts on coastal sounds and large lakes, November to March

Behaviour

Greater scaup dive for shellfish and plants, often gathering in large rafts on open water. They feed day and night, swallowing small clams and mussels whole and crushing them in the gizzard.

Why they matter

Greater scaup breed around the whole northern hemisphere and winter mostly on salt water. By feeding on shellfish they depend on clean coastal waters, and they are among the ducks most affected by contaminants that build up in the animals they eat.

Reproduction and lifecycle

Nest — A down-lined bowl on the ground near water, often on islands
Eggs — Usually 7 to 9
Incubation — About 24 to 28 days
Ducklings — Leave the nest within a day
Flight — At about five to six weeks
Lifespan — Wild birds over twenty years are recorded

Living around people

Scaup rafts on coastal waters are sensitive to oil and to disturbance from boats.

Misconceptions

Greater and lesser scaup can be told apart by size alone. They overlap; head shape and the wing stripe are better clues.

Related species

Seasonal activity

When this species is breeding, and when there are nests on the ground. Mowing during the shaded months is how most nests are found.

Breeding and active nests by month for this species
	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Breeding	Jan: no	Feb: no	Mar: no	Apr: no	May: no	Jun: no	Jul: no	Aug: no	Sep: no	Oct: no	Nov: no	Dec: no
Active nests	Jan: no	Feb: no	Mar: no	Apr: no	May: no	Jun: no	Jul: no	Aug: no	Sep: no	Oct: no	Nov: no	Dec: no
Notes	Wintering on the coast	Wintering	Migrating north	Moving to northern breeding grounds	Nesting on tundra lakes	Nesting	Ducklings hatching	Young growing	Young flying	Migration begins	Arriving on the Atlantic coast	Wintering

Where it lives

Recorded in 59 states and provinces. Each one links to the other animals there, and to the rehabilitators licensed for them.

Canada

If you found one

Answer a few questions and you will get a specific answer for what you are looking at.

I found an animal