Home & Garden Columns

Surf Scooter: From the Bay to the Boreal Forest

By Joe Eaton, Special to the Planet
Tuesday January 16, 2007

Among other signs of impending geezerhood, I keep noticing that some birds that used to be common are harder and harder to find. I can remember winters when the bay seemed to be paved with surf scoters. 

But these odd ducks, and their relatives the white-winged scoter and the black scoter, seem to be in trouble; populations of all three species have declined since the late 1970s. The biologists aren’t sure why, although there’s a whole Orient Express parlor car full of suspects. 

You can see the trends if you go to the Audubon Society’s Christmas Bird Count website and play around with the graph-making function. On the Oakland count, which includes Berkeley, surf scoter numbers have always fluctuated, but in the last decade or so the highs have been a lot lower. 

The Point Reyes count used to record white-winged scoters in the thousands on Tomales Bay. Last year there was only one. 

So what’s going on? It’s probably not overkill by duck hunters; none of the scoters are prized game birds, at least on this coast. They’re not among the tastier ducks. I have a couple of New England scoter recipes that appeared in Field and Stream in 1924. 

In one procedure, you boil the scoter and an anvil in a large pot. When you can stick a fork in the anvil, the scoter is done. Alternatively, you can nail the duck to a plank, leave it in the sun for a week, and then throw away the scoter and cook the plank. You get the idea.  

One concern is that scoters are picking up contaminants on their wintering grounds that interfere with reproduction. Scoters, like sea ducks in general, aren’t prolific breeders. They’re slow to mature and may not nest every year. So relatively small perturbations could have a disproportionate effect on population trends. 

Wintering scoters feed primarily on mollusks, supplemented by herring roe during spawning runs (they’ll pull up roe-encrusted eelgrass by the roots). And clams and mussels from San Francisco Bay, where over three-quarters of North America’s surf scoters spend the winter, are loaded with mercury, selenium, and cadmium. 

Those elements enter the Bay from runoff from old mines, irrigation drain water, discharges from oil refineries. In the 1980s, surf scoters in the Bay had higher mercury and selenium concentrations than any other species of waterfowl. 

The Bay’s changing ecosystem could be a factor in the ducks’ increased contaminant loads. The exotic overbite clam is a super-concentrator of selenium, at rates three times higher than other local clams. Changes in the prey base may also affect the scoters’ general condition. If they don’t return to the breeding grounds with the right ratio of protein to fat or the right body mass, they may forego nesting. 

There used to be huge gaps in our knowledge of the surf scoter’s life cycle: where and when it nests, where it stops over during migration. 

That’s changing rapidly, though, with ongoing studies in San Francisco Bay, Baja California, Puget Sound, and the Strait of Georgia. 

U.S. Geological Survey researchers have used satellite telemetry to track scoters from the Bay to nests in the Canadian Northwest Territories and sample their eggs for contaminants. 

The ducks may also bear the brunt of changes in the Far North. More than 80% of the population of all three scoter species breed in wetlands surrounded by boreal forest. 

Their decline is paralleled by that of other boreal nesters. It’s been a while since I’ve seen a Bonaparte’s gull, a graceful bird that, unusually for a gull, nests in trees. The rusty blackbird, formerly abundant in the East in winter, 

has also crashed. 

In all, 303 bird species, 43 percent of the North American total, nest in the Alaskan and Canadian boreal zone. It’s particularly important for migratory songbirds: flycatchers, sparrows, warblers. In the grand scheme of things, the boreal forest may be as crucial a habitat for North American birds as the tropical rainforests where other migrants spend the winter. And it may be just as vulnerable. 

According to the Boreal Songbird Initiative, only 8 percent of the Canadian boreal forest has any kind of formal protection. 

About a third has been earmarked for logging and energy development; millions of acres are clearcut every year. The current Conservative government in Ottawa is likely to exacerbate that trend. 

Logging aside, there’s our old friend global warming. A 1997 study found that the Mackenzie Basin in the Northwest Territories had warmed an average of 3.1 degrees F over the past hundred years, three times the global rate, and that Great Slave Lake, the deepest lake in North America, had reached its lowest measured water levels.  

For more on boreal birds and their environment, and suggestions for action, check out BSI’s website: www.borealbirds.org. Despite its name, the organization isn’t just about songbirds. Ducks, gulls, and shorebirds are also on its agenda. 

Surf scoters aren’t considered endangered—yet. But preventing that will likely take coordinated attention to both their Pacific Coast wintering grounds and their northern breeding territories.  




Photograph by Ron Sullivan  

A drake surf scoter near Oakland's Arrowhead Marsh.