The Daily Bird: Red-breasted Merganser

April 2, 2020
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Red-breasted Merganser
Mergus serrator

Originally published December 20, 2017

by Helena Ives
The Red-breasted Merganser’s distinguishing characteristics are a long neck, a scarlet bill, and a double crest at the back of the heads of both males and females.

The breeding male Red-breasted Mergansers have the rusty, black-speckled breast plumage described in their name, a dark back with long white patches along the wings, and a black and green iridescent head. Females and nonbreeding males, have a rusty brown head that extends to the back of the neck, a pale breast, and a dull grey breast, back and wings.

Where to find it: Typically staying within 20 miles of the coast, the Red-breasted Merganser has a more prominent preference for salt water, compared to the other two species of merganser.

In coastal areas and larger bodies of water, Red-breasted Mergansers can be found in large groups, as big as 50 to 60 individuals at times. Within Connecticut, Red-breasted Mergansers can also be found on inland lakes, ponds, or rivers in smaller numbers and with less frequency.

Check Bluff Point State Park, Hammonasset State Park, and Connecticut Audubon’s Coastal Center at Milford Point.

During breeding season, the species is predominantly found in the most northern portion of North America. As fall progresses, Red-breasted Mergansers return to their wintering grounds on both the Atlantic and Pacific coastlines of North America.

Conservation status: A part of the sawbill family, Red-breasted Mergansers feed on fish and crustaceans by diving into deeper portions of coastline. Historically, humans have targeted the species during waterfowl hunts because they were mistakenly thought to be depleting populations of salmon and trout, which were sought after by game fishermen and which were actually declining from overfishing.

Today, Red-breasted Mergansers are listed as a species of least concern and their population is stable.

Cool facts: Although the lifespan of most waterfowl species of similar size is around seven years on average, the oldest recorded Red-breasted Merganser was a female that was at least 9-1/2 years old, according to the data on her leg band.

Helena Ives is a naturalist for the Connecticut DEEP at the Goodwin State Forest and Education Center in Hampton. Previously, she worked for Connecticut Audubon monitoring birds as part of the Audubon Alliance for Coastal Waterbirds.

Photo by Mykola Swarnik