Surf Scoter: The Conspicuous Duck

By Stefan Marti
Published: October 2006

A male and female surf scoter in the ocean.

The Surf Scoter—aptly named for its tendency to forage in ocean surf and breaking waves—has earned a few other nicknames on the way: Skunk-head, Groggle-nose, and Mussel Bill to name a few.

Every winter these beautiful, white-spotted ducks with large Roman bills migrate to the shallow coastal waters of the Pacific, from Alaska’s Aleutian Chain to Baja California. From October to March, they are often spotted in the Gulf of the Farallones National Marine Sanctuary.

Adult male Surf Scoters are distinguished by their bright, bulbous, yellow and red bills. They have velvety black plumage, white patches on the forehead and back of the neck, and weigh about 2.3 pounds—the size of a California Gull. Females are slightly smaller, have brownish-black feathers and two whitish patches on the cheek.

Nesting

The surf scoter is one of the least studied ducks in North America. They nest in isolated areas in Alaska and Canada, and their nests are well concealed in boreal forests and tundra, typically in inaccessible vegetation near shallow lakes.

During breeding season, drakes (male ducks) viciously peck at rivals and there is a great deal of splashing in the water. Aggressive battles culminate with a skidding stop near a prospective mate. The dominant male will then defend his mate until the eggs are laid.

Females lay 6-9 eggs and incubate for 29 days.  After the ducklings hatch, it takes them 55 days till they can fly. Often mothers abandon their young before they can fly and return to the coastal waters to molt.

Diet

During the summer, surf scoters feed on freshwater invertebrates and insects such as beetles, flies, roundworms, spiders, and leeches. In the winter, when they return to ocean waters, they prey on mussels, clams, herring eggs and sand crabs.

"Sand crabs, an intermediate host for a parasitic spiny headed worm, make up part of a surf scoter's diet," says Amy Dean, FMSA Manager of Education Programs. "Surf scoters that forage on sand crabs can become infected with these parasites and can die. In fact, in 1995 1000-4000 surf scoters died due to an unusually high load of these parasites. We are currently working with high school students to monitor the parasites in the sand crabs. We hope to learn more about the patterns of parasite abundance in the crabs and the potential risk of infection to surf scoters. This project is part of a larger, coast wide long-term monitoring project for students."

Migration

Surf Scoters are quiet, non-vocal ducks (only gurgling and croaking during mating season), so you won’t be hearing them in California. They are often hard to distinguish from other scoters, although they have slower wing beats and seldom fly in lines. Instead, they tend to bunch up in large irregular formations.

The major winter flocks congregate off ocean beaches, where the ducks can be indifferent to intense human activity. They rarely dive more than 30 feet underwater, thus they stay close to shore. Sometimes when Surf Scoters are foraging for food, gulls will swoop down and steal their prey as they emerge from the ocean.

While Surf Scoters remain reasonably numerous, there is evidence of a considerable decline in the early part of the 20th century. A decline may be still be occurring, especially in the northwest, possibly due to oil spills and pollution losses at sea (as evidenced by Beach Watch volunteers).

However, if you’re at the beach and spot a black velvety duck with a white forehead diving through a foaming wave, it’s probably a Surf Scoter. "November is the peak month for seeing surf scoters off California Sanctuary beaches," says Beach Watch supervisor Shannon Lyday.

 

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