Waterfowl — and about 40 species of ducks, geese, and swans have been recorded on Martha’s Vineyard — may seem to be a boring group. Some species are abundant, at least seasonally, to the point that one gets tired of them. Even the uncommon species typically exhibit unexciting behavior, spending most of their time just sitting on the water. And often, these birds must be viewed at long range, where the subtleties (if there are any) of their plumage aren’t evident.
But there are ducks, and then there are DUCKS. Some of our waterfowl species are stunningly beautiful birds, if you can get a good look at them. And some have fascinating life histories featuring dramatic migrations, unusual habitat preferences, and biological oddness that can’t fail to attract a birder’s attention.
Exhibit “A” is the aptly named harlequin duck, Histrionicus histrionicus. The females of this peculiar species, I’m sorry to report, are drab, gray-brown ducks unmarked except for a pair of white spots on the side of the head. If you’re not on your game, it’s easy to pass one off as a female of the smaller, very common bufflehead, or one of the larger, also very common scoter species.
But the males are, without doubt, one of the prettiest birds in the world, with an elaborate pattern of white streaks and patches on their heads and chests. The pattern evidently suggested the motley of a court jester in some early ornithologist, accounting for both the common and scientific names of this duck. See a crisp adult male harlequin duck in good light at reasonable range, and I guarantee your jaw will drop in surprise.
Many of our sea ducks show little preference for any particular type of shoreline, concentrating in any area that features sheltered conditions and a good supply of food. But the harlequin duck is a notable exception: This species associates strongly with rugged, rocky coastline, the rugged and rockier, the better. They feed by diving among the rocks, and I have no idea what sort of skills keep them from getting smashed against boulders by the force of the waves. But somehow, these ducks pluck their living, in the form of a wide range of invertebrates, from the rocks and weed in their favored foraging sites.
This strong habitat preference points a Vineyard birder in very specific directions when looking for harlequin ducks. With remarkably few exceptions, records of this species come from places where eroded moraine has left underwater rock fields behind, or where human engineering has added rock to otherwise sandy shoreline. The best spot for harlequins, regrettably, is Squibnocket Point, where more than 100 of these ducks have sometimes been recorded, but a daunting gate deprives mere mortal birders of legal access. But a few harlequins can usually be spotted from the publicly accessible parking area at Squibnocket.
Other promising sites include below the Gay Head Cliffs, along the rip-rap shorelines of East Chop and West Chop, and occasionally even next to the breakwaters and groins across from Oak Bluffs’ Ocean Park and Farm Pond. The species is invariably present around the Island in winter, though numbers are small and favored locations are few. You can find them if you persist.
Gregarious birds, harlequin ducks turn up much more commonly in small groups than as individual birds. They tend to sit close together on the water, bobbing in the waves, and members of a flock tend to dive in unison. Between these behavioral quirks and the limited distribution of these birds around the Island, an alert observer can often pick harlequins out at very long range.
During the breeding season, harlequin ducks nest along fast-moving streams far to the north of us. They are as deft in the turbulent waters of mountain streams as they are on wave-tossed water along rocky shorelines. A good-sized Western population, numbering in the low hundreds of thousands, breeds along coastal or mountain streams from the Northern Rocky Mountains into much of British Columbia and Alaska. One Eastern population, estimated at about 10,000 individuals, breeds in Labrador and Northern Québec, wintering along the Southwestern coast of Greenland.
And finally, the population from which birds on the Vineyard come breeds mainly in Newfoundland. This population is thought to number only about 2,000 birds. So a wintering site like Squibnocket, with scores of individuals even in a bad year, hosts a significant percentage of this entire population. Most of this population remains to the north of us in winter, with rocky coasts from Cape Ann, Mass., up into Maine and the Maritime Provinces offering ideal habitat. But the species winters regularly, if sparingly, as far south Chesapeake Bay.
Birding the coast in my mainland days, from the 1960s into the mid-1990s, I searched for years for these ducks before I finally spotted some, one happy day in 1988 on Cape Ann. Among some 50 years’ worth of memorable birding moments, that one still stands out: A group of about a dozen harlequins, the males with their outrageous markings, bobbing like corks and then diving in unison amid Atlantic breakers bashing the granite cliffs. Now, that is a duck worth watching!