One of the exciting things about spring is the visibility of wildlife that are courting, forming pair bonds and beginning the task of raising the next generation of their kind. The most visible—hands-down—are the colorful waterfowl that have arrived on our northern lakes, rivers, marshes and ponds. At this time of year I carry binoculars, or a camera with a long lens, whenever my travels might take me past a lake or wetland. If I was a bumper sticker sort of guy, I would have one that reads “This vehicle makes frequent stops to watch wildlife.”
For the better part of a week I’ve been watching a large band of ducks on a local lake. At times I’ve estimated their number at 150, perhaps more. When waterfowl gather in such numbers you can’t be sure of the identities of all. But my binoculars revealed that most were of a variety known as common mergansers. Most of these birds will only be transient visitors, and the majority will nest farther to the north in Minnesota, or in Canada.
Like people, some wild creatures bear nicknames, and the common merganser is cursed with the nickname “fish duck.” It is descriptive of the way they make a living, for a large share of their food is secured by diving beneath the surface and capturing fish, including minnows of various kinds, and the immature and smaller members of some rough fish and game fish.
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Mergansers are well-suited to this lifestyle, with a bill that is unlike the broad, flat bills of most ducks. Theirs is narrow and studded with tiny tooth-like nubs that are perfect for grasping swimming, wriggling prey. If you’re familiar with the electrical connectors called alligator clips, you have a very good idea of what a merganser’s bill looks like. This unique adaptation has also earned mergansers—there are three types common to North America—the name “sawbill.”
Humans have a selfish streak when it comes to things we want for ourselves, and that includes fish. A merganser can engulf and swallow fish significantly larger than its bill would suggest. Farther north, many will nest and raise their young near streams and rivers, some of which are trout streams and salmon rivers. This does not endear them to salmon and trout fishermen, in the same way that some of us resent the fact that wolves prey on deer, hawks prey on ruffed grouse, or a roving skunk will make a meal of mallard eggs. With limited exceptions, such predator-prey relationships don’t threaten a population as a whole, or claim a share that should be ours. All life doesn’t exist entirely for our benefit.
The common merganser is looked down upon for other reasons, at least by some. Their fish-eating lifestyle gives the common merganser’s flesh a stronger flavor than many other ducks. Many waterfowl hunters shun them for that reason, though our own food consumption peculiarities—anchovies or liver, for instance—might disqualify us from being too judgmental.
In poor light, or due to inexperience or excitement, a hunter might shoot before positively identifying a duck over his decoys—it happens more frequently than it should. When the hunter or his canine companion retrieves the fallen, and the hunter sees the narrow bill studded with tiny tooth-like serrations—unmistakably a merganser—you might hear an oath or profanity expressing displeasure. Some duck hunters would conceal, rather than reveal, their downing of a “fish duck.”
There are other ducks that feed heavily on fish, snails and other underwater life from the animal kingdom, a habit that makes them strong to the taste, too. But somehow mergansers have come to be most associated with shortcomings on the table; especially if the diner is used to eating mallards, wood ducks or teal—which eat mostly plant foods. Mergansers and some of the other “diving ducks” will test the boundaries of your taste buds, or your skill at disguising flavors.
Notwithstanding this liability in the taste department, I find the common merganser appealing. I’ve watched this large flotilla riding the whitecaps over deep water in heavy wind, their strung-out flights skimming just above the wave tops, communal mating displays and their diving to feed in shallow water, popping back to the surface like corks before diving again. Mergansers seem especially social birds, even at a time of high competitiveness when every breeding age male is vying for mating rights, and the opportunity to pass on its genes to the next generation.
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For a duck that is so often “dissed,” the common merganser is uncommonly handsome. Drakes have a dark, green-black head, and predominantly white plumage contrasting with black that gives them a tuxedo-like appearance. Hens, as in most birds—including most waterfowl—are more subtly plumed, with a reddish brown head and gray back and flanks that grade into a white belly and breast. Female and juvenile common mergansers have an unusual, almost comical, Woody Woodpecker-like tuft of feathers projecting rearward off the top of their head.
In flight the common merganser’s wings appear longer than the stubby wings of other diving ducks, beat rapidly but in a shallow arc, and the drakes flash highly-visible patches of white on their upper wings, a reliable identifying mark.
Common mergansers share some loon-like characteristics, not surprising since both are so well adapted to a life of catching fish. Both loons and mergansers will often be seen swimming with their head half submerged, looking beneath the surface—“up periscope” in reverse—a strategy for spotting swimming prey before diving in pursuit. Both common mergansers and loons have a more elongated, streamlined body than most waterfowl, a hydrodynamic advantage when swimming underwater in pursuit of prey. Mergansers will sometimes paddle and splash along the surface in a group, herding prey fish to enhance their capture prospects.
Soon most of this large gathering of common mergansers will depart for nesting areas to the north. Perhaps surprising for a mallard-size duck, most will nest in a hollow tree cavity if they can find one, another good reason not to cut down a large tree just because it’s dead and decaying.
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Despite my affection for the common merganser, it's unlikely that I’ll intentionally harvest one during the hunting season. If I do make that mistake, I’ll pull out the recipe file labeled “Gamey Ducks,” and make the best of it!
