Thurston's Birds

Scoters – marine birds of winter 

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If the only birds you see are the ones at your bird feeder or those birds you see around the neighborhood; you may not be familiar with some of our more common birds of winter, the scoters.

There are three species of these medium to large marine ducks. Their genus name, Melanitta, comes from Greek meaning “black duck” because the feather color of males is primarily a velvety black.   

The scoters winter range in Thurston County is strictly saltwater; they are never seen elsewhere. They feed by diving, sometimes quite deep. Clams and mussels are preferred prey. They return to the surface before swallowing their catch, so if you see them close to shore you might be able to identify what they’re eating.  

They swallow those clams and mussels whole, and then perform remarkable feats of digestion. As you likely noticed, birds do not have teeth and therefore, with some exceptions for large predatory birds, they swallow their food whole. To digest their food, they have a grinding organ, the gizzard. 

The gizzard is a strong muscular organ capable, with the assistance of grit that the bird swallows from time to time, to grind food up before it passes to its stomach for digestion. In essence, the gizzard replaces the teeth that mammals have for chewing food. 

Scoters and their gizzards provide an interesting contribution to shoreline and nearshore ecology. Once the clams and mussels they eat are ground up, the materials pass through their intestinal tract, where nutrients are absorbed. Then the remains are excreted as ground up shell.

When you next visit a Puget Sound beach, take a close look at the sand. Do you see bits of white? There’s a good possibility that those bits of shell passed through a scoter’s butt! 

Scoters, especially the surf and white-winged species, are quite common along our southern Puget Sound shorelines. Binoculars can be useful to see their details, but often they feed so close to shore that you can identify them, especially at high tide. You can look for them in the interior part of Budd Inlet, the shore of Squaxin Park and other parks with shore access, and from the Luhr Beach viewing site in the Nisqually Delta area.  

These three duck species breed in the far northern tundra parts of Canada and Alaska, and spend their winters along the marine shore areas of both the Pacific and Atlantic oceans. There are other scoter species that follow the same breeding and wintering pattern in Eurasia, and the males of these species also are primarily black.  

Surf Scoter, male.
Surf Scoter, male.

By far the most common in our territory is the surf scoter. The males are all black with a sloping bright orange bill and prominent white spots on the heads and backs of their neck. Their eyes have a white iris that is easy to see. The females, in contrast, are a dull brown with two small white patches on their heads. 

White-winged Scoter, male.
White-winged Scoter, male.

Less common, but often seen locally, is the white-winged scoter. Again, the male is primarily black, with a very noticeable white wing patch, visible when the bird is at rest and very obvious in flight (the other two scoter species do not have wing patches). This male also has an orange bill and white eye, but has a white comma-shaped mark at its eye. Females are brown with two white face patches. (Female surf and white-winged scoters are often identified by the males they’re with). 

Adult male Black Scoter.
Adult male Black Scoter.
Black Scoter female.
Black Scoter female.

The third scoter species, the black scoter, is now rare in Thurston County, although decades ago it was more common. The Olympia Christmas Bird Count data show this decline, but not the reason for it. Its total North American population size, while smaller than the other two scoter species, is still robust and wintering numbers in Puget Sound have not declined. Our South Sound decline is a minor mystery. 

The black scoter male is all-black (no white eye for him) except for a bold orange knob at the base of its bill. The other scoter males also have such knobs, but they are less obvious since they do not contrast in color like the black scoter’s. The female is brown overall, but has a pale face that contrasts with its deep brown cap, which makes them uniquely different from the other scoter females. 

When seen together, scoter species can be separated in several ways. First, for the males you can “look them in the eye” – they all have very different eye appearances. Second, their sizes are different – the black scoter is smaller, followed by the surf, and then by the larger white-winged. And, finally, only the white-winged, both male and female, have white wing patches. 

Even if you never master the differences between these three species, you can take pleasure learning to name scoters by the basic black that all the males wear. 

George Walter is environmental program manager at the Nisqually Indian Tribe’s natural resources department; he also has a 40+ year interest in bird watching. He may be reached at george@theJOLTnews.com 

Photos for this column are provided by Liam Hutcheson, a 17-year-old Olympia area birder and avid photographer.

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