Wildlife Clinic

Species

Red-breasted merganser

Mergus serrator

A shaggy-crested, fish-hunting duck that winters in Georgia's sounds and bays in large, busy flocks.

A male red-breasted merganser swimming on grey water, his shaggy green-black crest and thin red bill in profile.

Photo Needsmoreritalin (opens in a new tab) / Wikimedia Commons, CC BY-SA 4.0 (opens in a new tab)

At a glance

Size
About 51 to 64 cm long
Weight
About 800 to 1,350 g
Habitat
Coastal sounds, bays, inlets and large lakes
Diet
Small fish and crustaceans
In Georgia
A common winter visitor on the coast
Voice
Mostly quiet
Rabies vector
No

Identification

Key marks
Long, thin, serrated red bill; shaggy double crest
Male
Green head; white collar; speckled rusty breast; grey sides
Female
Grey body with a rusty head that fades into the neck
Told apart from
Common merganser, a rarer visitor, whose male has a clean white breast and female a sharp line between head and neck
Where to look
Coastal waters and inlets, November to April

Behaviour

Red-breasted mergansers hunt fish in groups, sometimes swimming in lines to drive fish into shallow water. They are among the fastest-flying ducks.

Why they matter

Mergansers are skilled underwater hunters, and their thin, saw-edged bills are an adaptation for gripping slippery fish. They rely on healthy schools of small fish in coastal waters, which also feed pelicans, dolphins and many other animals.

Reproduction and lifecycle

Nest — A down-lined hollow on the ground, hidden under shrubs, near northern coasts and lakes
Eggs — Usually 7 to 10
Incubation — About 29 to 35 days
Ducklings — Leave the nest within a day
Flight — At about eight to nine weeks
Lifespan — Wild birds over ten years are recorded

Living around people

  • Fishing line and lures are a hazard for mergansers that chase fish near piers and jetties.

Misconceptions

  • Mergansers are not real ducks. They are ducks, specialised for catching fish.

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
JanFebMarAprMayJunJulAugSepOctNovDec
BreedingJan: noFeb: noMar: noApr: noMay: noJun: noJul: noAug: noSep: noOct: noNov: noDec: no
Active nestsJan: noFeb: noMar: noApr: noMay: noJun: noJul: noAug: noSep: noOct: noNov: noDec: no
NotesWintering in flocksWintering; courtship displaysMigrating northLast birds leavingNesting in the northDucklings hatchingDucklings growingAdults moultingYoung flyingMigration beginsArriving on the coastWintering

Where it lives

Recorded in 65 states and provinces. Each one links to the other animals there, and to the rehabilitators licensed for them.

If you found one

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

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