Underwater With the Surf Scoters of Burley Lagoon

Here’s to a new year of life on the Key Peninsula.

When I say life, I mean life abundant, life wild, life filling every crevice of our backwoods and bays. Our peninsula is many things, chief among them diverse and ever-changing.

For the naturalist, it offers an endless train of surprises.

Here in midwinter, great horned owls are performing duets as they prepare to nest. In a ditch by our home, water beetles of some bronze-ish variety are active at night though the water is 39 degrees. In the woods, beaked hazelnut trees will soon unleash their yellow catkins, the first wildflowers of the year.

My explorations are guided by readers. Why don’t you drop me a note this year, let me know what you’re seeing and wondering about in your neck of the woods?

Pause on the Purdy Spit. Look on the lagoon side. What do you see? A rambunctious crew of surf scoters, hundreds strong, bouncing around like bumper cars.

Surf scoters are migratory sea ducks. They are only here in the colder months. A male surf scoter, black all over, is instantly recognized by its goofy orange-and-white beak and a white neck patch that is vaguely mullet-like. The female’s beak is similarly chunky, but it matches her body’s dark ashy gray.

See them dive. Without warning, one cocks its wings at a severe angle and throws itself head-first in to the water. The rest of its crew, seeming afraid to miss out on the action, follows suit. Sometimes the now-empty water roils with their underwater adventures. Then up they come, bumping and biting at tails. They are the definition of unsynchronized. Maybe one in 20 has a clam or crab in its beak and promptly swallows it whole, before the others notice.

Shellfish have long been considered a surf scoter’s favorite food. The ducks congregate over sandy areas for clams and rocky reefs for mussels. Watch the Burley scoters and you’ll see. The shellfish industry stakes nets over its harvests.

Recent research, however, suggests that past studies of surf scoter diets have exaggerated the shellfish component. It makes sense. If the tools at your disposal, as a researcher, are observation and the inspection of a scoter’s gizzard, where hard food is ground to pieces, you’ll mostly note large, hard prey items. In fact, surf scoters have a wide-ranging palate that has them seeking out a variety of soft-bodied sea creatures, small crabs, marine snails, marine worms, even vegetation.

Maybe the past studies are also a reflection of the way we sit up and take notice when an animal eats something we want to eat, like a clam.

Surf scoters occasionally decamp from their usual haunts, like gold rushers on a stampede, to plunder the sort of massive food pile that can sometimes appear in the sea.

In the spring of 2003, researchers in British Columbia, following scoters to a place where they had gathered in a great frenzy, dispatched a diver who found “a large continuous gelatinous matrix ... surrounded by loose decaying algae,” according to the report published in “Marine Ornithology” in 2005. Embedded in the mass of gel were millions of young polychaete worms.

The scoters were feasting. A gray whale joined. Little is known about the species of polychaete worm involved, except that when it goes to breed, it gathers en masse to join mucous tunnels into huge net-like structures that aim to overwhelm predators with abundance, like an oak that suddenly drops thousands of acorns.

A more common bonanza for surf scoters is herring spawn.

Up and down the northwest coast each spring, herring stocks synchronize their egg-laying. One morning, all at once, just below the low-tide line, billions of herring eggs will coat every rock, branch and blade of algae. The eggs last two weeks before they hatch and are gone. Scoters go wild for them.

In the south Puget Sound, where herring numbers are at a fraction of their historical abundance, we have recently been treated to a glimpse of this phenomenon.

A Purdy stock breeds both inside and outside the lagoon. It had a banner year in 2023. The Washington Department of Fish and Wildlife estimated 3,031 metric tons of herring spawn at Purdy. The previous high in 16 years of monitoring was 884 metric tons.

Herring spawn is one of the key indicators used by Puget Sound Vital Signs, a multi-agency effort to track Puget Sound’s overall health.

The herring trends have been mixed. Unlike elsewhere in the Pacific, Puget Sound stocks overlap geographically and spawn throughout a six-month window, and when numbers go up in one area they often go down in another.

That the bonanza swirls unpredictably was actually a boon to indigenous people in the Northwest. The genetic diversity of herring, like that of salmon, creates a more varied food landscape in an ecosystem where individual stocks often boom and bust. Diversity is a form of security.

A Vashon Island archeological site had 10 herring bones for every salmon bone. Salmon get the press, but herring were just as important to the Nisqually and Puyallup peoples, who raked adult herring from the sea and dried and smoked them in great numbers. At spawning time, tribal members blanketed the tide flats with cedar boughs. When the boughs were covered with eggs, they pulled them in and feasted and dried basketfuls for storage.

In British Columbia, anthropologist Franz Boas found Kwakiutl people using herring spawn to bait traps that were anchored underwater to catch sea ducks. Scoters were probably on the menu, given their love of herring spawn.

Around Purdy, scoter numbers shift from year to year. Data from eBird suggests that surf scoters have declined by about 10% in the past decade in the South Sound.

When you go to see them, watch for the “scoter salute” — a scoter when it comes in for a landing on the water lifts its wings briefly to the sky as it skids to a stop.