by Darcy Thomas
There are some birds we expect to see in certain locations and the Black Scoter (Melanitta americana) is one of those birds. It is, after all, a sea duck so one would expect to see them in open salt water. I viewed scoters many times along the Washington Coast and Puget Sound and had never thought about them venturing inland. On one occasion my husband and I watched as a small group of Black Scoters were diving to collect clams. They swallow them whole, crushing them in their gizzard, which is filled with sand. The crushed shell is then regurgitated. But not all the scoters were successful in swallowing the clams. Flying overhead vigilant Western Gulls circled, swooping down in a timely fashion when a scoter tilted its head up to swallow and forcing them to drop their clams. Quickly, the gulls snatched the clams before they had a chance to sink then flew to the beach dropping them on rocks to crack them open so they could feast.
When I became aware of the presence of Black Scoters in the Flathead during the fall I perked up. What factors come to play to bring seabirds inland during migration? Out came the books. I had to find out. As it turns out, Black Scoter breed in northern Quebec, Labrador, and Alaska on coastal tundra and lakes. Females build a nest on the ground near water. The nest is a shallow depression lined with soft plant material and down and hidden by grasses or shrubs. She lays 8-9 eggs which are incubated for one month. Males defend the area around the nest. The young fledge at 6-7 weeks. While females attend the brood at night the young forage along with adult scoters during the day. Food consists of marsh insects in summer along with small fish, fish eggs, and plant materials (on fresh water). In winter the birds dive for mussels and bivalve mollusks.
When the breeding season is over in late June, Black Scoter migrate to temperate zones on both coasts. Males are the first to leave the breeding grounds. Over the summer they are followed first by non-breeding females, then breeding females and subadults.Western Black Scoters interrupt their southward migration to gather in calmer inshore waters at annual molting sites throughout Alaska, and the western parts of the Yukon and British Columbia.
Once they are finished molting and their flight capability returns, Black Scoter continue with their migration. Most of them continue migrating along the Pacific Ocean as far south as northern Washington and the Puget Sound where they stay all winter primarily on saltwater bays. But a few of them make their way inland and will stay for a few weeks as rare migrants during the fall and early winter. They drop down onto a big lake for a brief stay to rest and eat before continuing to the coast. This is how they end up in parts of Montana such as the Flathead Valley on bodies of calm water like Foy’s Lake, Lake Rogers, Lake Mary Ronan, Lake McDonald, and Flathead Lake and the Creston wetlands. Look for them in deeper open water, not near the shore. A spotting scope can be useful to view the birds better.
The Black Scoter is the least common of three North American Scoters, the others being the Surf Scoter and the White-winged Scoter. Black Scoters are medium-sized diving sea ducks that are sometimes described as “simple elegance in evening dress”, with males sporting a glossy jet-black plumage with a striking yellow knob, much like a lightbulb, on their small bill. Females are dark brown with a pale cheek patch and a dark crown. Black Scoters are buoyant swimmers who propel with their feet. They do wing flap displays while swimming by flapping their wings with their body held up above the water and then thrusting their heads downward. They often cock their short tails in the air and can appear much like the Ruddy Duck in poor light when all you see is the silhouette. But the Ruddy is much smaller. In contrast to their dark bodies the undersides of their wings flash silvery gray when they are in flight. Birds take off from the water abruptly. Black Scoters are the most vocal of the waterfowl during the breeding season when courting males make a mournful-sounding whistle and melancholy coo. During the winter you rarely hear them so listen carefully for the whistling of their wings in flight instead.
Black Scoter populations appear to be in decline and are listed as near threatened. Hunting takes a big toll. Other conservation concerns include climate change, contaminants such as pesticides, oil spills and other pollutants, as well as habitat degradation such as oil and gas drilling in nesting grounds. Shipping traffic can discourage them from utilizing good feeding grounds as well.
Much still needs to be learned about Black Scoter such as its basic breeding biology. Ornithologists need to do a comparison of Western and Eastern populations, learn more about their winter habitat, and how hunting affects breeding populations. In fact, there is a long list of questions regarding Black Scoter that could keep ornithologists busy for many years.
References available upon request from firstname.lastname@example.org.
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