The most common scoter, or ocean duck, along the Pacific coast is the Surf scoter (Melanitta perspicillata). This salt water duck is found from Alaska south into north-central Canada, and all along the west and east coast of the U.S.
The Surf scoter overwinters by the thousands off the Oregon coast and are abundant here from fall through spring.
The bulk of this species overwinter in boreal forests in Alaska and Canada near freshwater lakes. Birds may also visit large lakes and reservoirs west of the Cascades in the fall.
Surf scoters are the smallest of three similar species (white-winged, black, and surf), which are often found in the same habitat.
Adult male Surf Scoters are around 19-inches in length and just over 2.3 lbs. Females come in just a bit shorter.
Adult male feathers are predominantly black with two white patches (forehead and nape). The colorful wedge-shaped bill is highly visible with white, yellow, red-orange, and black.
Adult females and subadults have a dark brown back, lighter brown belly, and light-colored patches on cheeks and nape.
Generally, compared to the other two species, the head profile is more flat, and bill heavier. The surf scoter has completely dark wings (visible in flight).
The species, however, does not breed in Oregon. Surf Scoters breed in Alaska and across north-central Canada.
Most form pairs before arriving at the breeding ground with males and females migrating together. Flight is strong and close to the waves.
Individuals appear to adjust their migration schedule so that they meet at the wintering and staging grounds at the same time. This helps the birds optimize reproduction.
Females build nests that are bowl-shaped and lined with debris and down. Up to nine eggs in each nest are incubated for nearly a month by the female.
Nests are tucked into crowded breeding grounds and occasionally brood errors are made. The synchronous egg hatch must be a totally amazing event to witness.
Surf scoters forage in the surf, typically in open waters less than 33 feet deep. They dive in regularly flooded intertidal and subtidal zones.
While mussels are an important part of their diet these ducks will feed on any invertebrate found in or near the near shoreline sediments. This could include insects, crustaceans, herring spawn, coral, algae, shrimp, oysters, crabs, squid, clams, and more.
They generally capture and swallow their food whole under water. These birds will often form loose flocks to forage that move in irregular, wavy lines. They will often do this as a group, or loose flock.
Dive duration varies based on prey, water conditions, season, etc. This duck will also shift their diet as needed in winter and spring to more abundant prey.
The Matter of Molting
All waterfowl molt their feathers one or more times a year. For Surf scoters this process begins before migration in late July and lasts for about four weeks.
Surf scoter travels to a molting site (different than the wintering or nesting sites) in bays, inlets, or estuaries. These sites would most likely have easily available food and lower predation risk.
Sea ducks are vulnerable during the molt because they lose their flight feathers. Brightly-colored male plumage is also replaced by duller plumage.
Predators and Survival
These birds typically winter in marine habitats near rocky shores. Predators can include bald eagles, golden eagles, and carnivorous mammals.
Birds are particularly sensitive to oil spills. Spills impact food supplies and are known to kill many birds through starvation.
In the last 50 years, the population has somewhat declined but is not considered vulnerable.
–Oregon Dept. of Fish and Wildlife, Swans, Ducks, and Geese (https://myodfw.com/wildlife-viewing/species/swans-ducks-and-geese)
–USDI Fish and Wildlife Service (https://www.fws.gov/r5gomp/gom/habitatstudy/metadata/scoter_models.htm and https://www.fws.gov/birds/bird-enthusiasts/bird-watching/waterfowl-identification/surf-scoter.php)
–Wikipedia, Surf Scoter (https://en.wikipedia.org/wiki/Surf_scoter)