Seeing these sea birds isn't necessary if you can hear them

The duck flock was tight on the water about a quarter-mile away. We were standing on a cliff overlooking Lake Superior along Hwy. 61, a half-dozen miles down the lake from Grand Marais, Minn.

You could identify the birds with binoculars. Or, you simply could listen to them muttering among themselves, the faint sounds of duck conversation floating across the water.

These were long-tailed ducks. I heard them muttering. Roger Tory Peterson, in the fourth edition of his field guide, describes the ducks as talkative and musical. The National Geographic's "Complete Birds of North America," second edition, says female long-tails are "highly vocal."

David Sibley in his identification guide describes the voices as soft grunting or quacking, like "url url" or "kak kak kak." He hears the same male voice as reported in National Geo, "a loud yodel."

We were not treated to anything like yodels, just faint conversation far out there on the water.

The Cornell Lab of Ornithology says the birds are ducks of cold northern waters, "often the most abundant bird in the high Arctic, wintering on the Bering Sea and Hudson's Bay."

They also move south in the winter to both of our coasts, appearing on the Great Lakes during migration. Our sighting must have been in late winter, on the trip north. They make annual appearances on Lake Superior.

Long-tails feed on mollusks and crustaceans, known to dive more than 200 feet in search of food. The flock we saw disappeared into Superior for what seemed like minutes. Just when we began to wonder where they went they would pop to the surface.

Long-tailed ducks are sea ducks, a tribe of 15 species of the duck subfamily of birds.

Sea ducks nest in Minnesota, the appellation "sea" not restrictive. Nesters are common goldeneye, red-breasted, hooded, and common mergansers, and, on occasion, bufflehead.

Hooded mergansers are frequent users of nest boxes. Several merganser families fledged from the duck boxes in our Orono backyard over the years. It never occurred to me that they were sea ducks.

Regular migrants in Minnesota are black, surf and white-winged scoters, Barrow's goldeneye and harlequin duck. Common and king eiders are infrequent visitors.

"Sea ducks are popular game birds in North America, yet they are poorly monitored and their population dynamics are poorly understood relative to other North American waterfowl," according to the website of the Sea Duck Joint Venture (SDJV), a conservation partnership under the North American Waterfowl Management Plan.

Sea duck life histories are characterized by high rates of adult survival. Unlike common duck species, which breed in their second season, sea ducks don't breed until they are three or four years old, according to the management plan.

They have low reproductive capacity, suggesting that population abundance of these species might be sensitive to hunting. There is concern about harvest numbers and habitat limitations, the plan states.

The SDJV's highest priority species are common eider, black scoter, surf scoter, white-winged scoter, harlequin duck and Barrow's goldeneye. For all these species there is a lack of baseline data, including numbers on historical or current population declines.

The North American population of long-tailed duck has been crudely estimated at one million birds.

Its range is extensive, but occurs mostly outside of areas covered by established waterfowl surveys. There is little information available to accurately estimate population size and trends for this species.

On a day in late winter you might get lucky, though, as you head up the lake on Hwy. 61, stopping where the view is good, listening for a flock of ducks on the water muttering among themselves, watching them pop to the surface after long feeding dives.

Lifelong birder Jim Williams can be reached at woodduck38@gmail.com.