Know your winter mergansers

Bruce Mactavish
Published on February 1, 2014

Mergansers are ducks. Of the 30 species of ducks that have occurred in Newfoundland and Labrador, only three are mergansers. In fact, there are only three species of merganser in all of Canada.

The merganser tribe is separated from the rest of the duck clan by their long thin bills with serrated edges. Mergansers have tiny tooth-like spines running along the edges of their bills made for grasping slippery fish. They are sometimes nicknamed saw-bills for this reason. These ducks are fish eaters. You will not catch them eating bread or pond weeds.

The three species of merganser are red-breasted, common and hooded merganser. The hooded merganser is the least numerous in Newfoundland and Labrador. Small numbers nest in central Labrador and there is one nesting record for the island. It is otherwise on the rare side on the island of Newfoundland with maybe a half dozen sightings per year at most.

Hooded mergansers are different than the other two mergansers. They are smaller. The drake is a beautiful bird with a white fan-shaped crest rimmed with black on the back of its head.

Unfortunately, most that we see on the island are females or immatures. They are duller brown with a dull orange crest. They are not usually difficult to separate from the females of the other merganser species. If in doubt, check the bill colour. It is mostly black in the female hooded merganser but all orange in the common and red-breasted merganser.

In this article, we will learn how to go about identifying the mergansers that you are most likely to encounter.

The common and red-breasted mergansers are widespread and numerous in Newfoundland and Labrador. They have some differences in habitat choices. The common merganser is more of a freshwater loving species in all seasons but is not restricted to lakes and rivers. It is often present in brackish water, where freshwater and saltwater mix in large river estuaries. And in winter, when freshwater habitats are frozen, they can be found in sheltered saltwater coves.

The red-breasted merganser is fond of saltwater except when it has to go inland to the larger rivers and lake during the nesting season. It is widespread around the coasts of Newfoundland and Labrador where there is regular open water during the winter. It is often known as the shellbird by hunters.

During the nesting season, they use brackish water in large river estuaries, but most nest inland on the larger rivers and lakes. Once finished with nesting duties, red-breasted mergansers are back on the coast.

Pretty boys

The rule among ducks, and most other birds, is that the males are prettier than the females. There is logical reason for this. The females want to look inconspicuous when sitting on the nest. The drakes have to look good to impress the females.

The differences between the drake red-breasted and common mergansers are pretty obvious. Red-breasted merganser is named for a band of rusty streaks across the breast but this is only part of the overall darker upperparts.

It also has a crested green head. The male common merganser is much whiter when sitting on the water. The sides and neck are white contrasting with the dark green head that lacks a crest. In some lights the white body is tinged with a peachy blush.

It should be noted that the green sheen on the head of both species looks dark unless observed in the bright sunlight.

The practised eye picks out the drake common merganser at any distance just by the amount of visible white. The whole side and neck with a contrasting dark head is really quite different from the dark and mottled sides and neck of the red-breasted merganser.

It is the females of the two species that present the identification challenge. It takes practise to get good at correctly identifying the female mergansers, but with a good look everyone can do with confidence.

Both have greyish bodies, a reddish-orange head containing crest and long tine orange bills.

The female red-breasted has a duller red head with a longer crest. The orange head blends gradually into the grey neck. The female common merganser has deeper red head with a shorter crest. The contrast between the red head and the white neck is cookie-cutter sharp. In addition the white throat patch is sharply demarcated on the common merganser but hardly noticeable on the red-breasted merganser. While there are various clues that help identify the female mergansers, it is the neck contrast, subdued in red-breasted and cookie-cutter sharp in common merganser, that is the best mark to clinch the identification.

Upon closer examination, you begin to see other differences. The common merganser is a slightly bigger bird. It sits heavier in the water almost like a loon. It has a slightly thicker bill. The red-breasted merganser is a slimmer more lightweight bird.

Where can you go to see mergansers?

Red-breasted mergansers are widespread in low numbers around the coast. Any coves and bays around the coast are likely to harbour a handful of red-breasted mergansers.

Common mergansers are more local in the winter. Good places on the Avalon Peninsula are the various coves in the bottom of Conception Bay, especially where a small river flows in.

Excellent locations for large numbers of common mergansers in winter are Shoal Harbour causeway near Clarenville and Port Blandford. Common mergansers are the dominate mergansers at these locations.

In the last week, there was a female red-breasted and common merganser at the west end of Quidi Vidi Lake, offering an excellent chance of comparison of the two species. Perhaps they will stay for a few more weeks.

Enjoy your mergansers.

Bruce Mactavish is an environmental consultant and avid birdwatcher. He can be reached at, or by phone at 722-0088.