From a tower overlooking three pairs of small artificial ponds in Laurel, Md., biologists study the feeding behavior of six duck broods, meticulously noting the birds' every move. Farther north, in Nova Scotia, a Canadian biologist keeps watch on the growth rate of ducklings on remote, nutrient-poor ponds and compares it with that of similar birds feeding in richer farm ponds and sewage treatment outlets. Elsewhere, a licensed trapper in the Maritimes lifts a huge, dark adult duck from a trap and removes the timeworn band from its leg, replacing it with a new one and mailing the old band to Washington, D.C. On a tidal marsh in New Jersey, a hunter picks up a duck he's just shot over his decoy rig, examines its feet and bill, clips a wing and stuffs it in an envelope. Then with a sigh he pulls in his decoys. Although the sky is full of ducks just waiting to toll into his blind, for him it must be another one-duck day.
All this activity—even the duck hunter's act of reluctant restraint—is in behalf of the black duck. Until recently, this big, shy, dark-feathered waterfowl with its coral-red legs and olive-green bill was the Crown Prince of the Atlantic Flyway, ranking second only to the Canada goose in the esteem of hunters along the East Coast from Cape Breton Island .to the Carolinas. There has always been something mysterious, almost magical, about "blackie." It is a bird of the dim hours, conducting much of its business in the gray half-light of dawn and dusk, often announcing its arrival over a blind with nothing more than the rip of powerful wings through the cold, dark air. To those who love it (and love to kill it), the black duck is at one with the boom of Atlantic surf on the nearby barrier islands, with the first pink touch of sunrise igniting the tips of the spartina grass, with the tang of salt and the dark iodine reek of marsh muck on patched but leaky waders.
From the sandy barrier beaches of Assawaman Island, on the Eastern Shore of Virginia, one can look north at sunset to the gantries and' blockhouses of NASA's rocket-launch range at Wallops Island, looming pale and misshapen in the pink light, an eerie echo of a turn-of-the-century Thomas Eakins painting. It is here that the black duck is making its last stand.
Cautious as a banker, a flock circles the decoys endlessly, remaining just out of range, checking the "blocks" from every angle. The slightest tag of weed fluttering underwater on a tide-swept anchor line will send it banking and whirling away, not to return that day, if ever. When the birds do pitch in, it's always at the edge of the decoy rig, and if a gunner rises to shoot before they have all committed themselves, they will be up and off again as if powered by retro-rockets. The black duck takes a lot of killing, but to thousands of waterfowlers since the days of the Pilgrims, it has been well worth it, especially when served up quick-roasted and blood-rare, with a pinch or two of sage and rosemary.
But now the black duck is in deep, perhaps irreversible, trouble. A generation ago hunters killed a million blackies a year along the Atlantic and Mississippi flyways (the birds occur only rarely farther west). Today it is estimated that there may be no more than a million and a half left in the world. Both the mallard and the wood duck now rank above the black in numbers taken by hunters each year along the Atlantic Flyway. Ironically, early in this century the wood duck was itself on the verge of extinction, and only a monumental effort by wildlife experts and duck hunters, aided by the return of farmland to a more natural state, brought it back to huntable levels. But skeptics fear that no such turnaround is likely for the beleaguered black. The species Anas rubripes, they say, is being hybridized out of existence.
The villain in this tale is the mallard, Anas platyrhynchos, that familiar green-headed paddler of every wet habitat from prairie potholes to city park ponds and suburban swimming pools. Some ornithologists theorize that the black duck species began breaking away genetically from the ancestral mallard some four million years ago. What evolved was a bird that resembled the hen mallard, but with a much darker color and a pronounced predilection for forest-country beaver ponds and East Coast salt marshes as its breeding and wintering zones. The mallard, in those days at least, preferred more open country—the pothole ponds of the Midwestern prairies. Some biologists believe that along the way the emerging black duck developed an immunity to a blood parasite called a leucocytozoan, which is transmitted by the blackflies that make the summer woodlands of New England and eastern Canada—the blackie's prime grounds—a living, biting, scratching, swatting hell for Homo sapiens.
All was well and good between the two species as long as they remained separate. But then, shortly after World War II, the population dynamics of the birds began to change. Black duck numbers began a sharp decline even as mallards thrived and spread. One of the major indicators the U.S. Fish and Wildlife Service employs to keep track of the shifts in duck population is the "mid-winter survey." which tots up the number of ducks found on the species' wintering grounds. The 1955 winter survey showed 760,900 blacks on the water between Canada and the Carolinas, and inland to the lower Midwest. By 1960 the winter count had dropped to roughly half a million, and in January '83 researchers could spot only 293,800.
Some 60% of this decline took place during the 1950s and early '60s. The sharp drop, amounting to more than 5% of the total black duck mid-winter survey figures in some years, coincided with the infamous postwar era of swamp-filling, when every bog, mire, swale, slough, marsh and fen within reach of a bulldozer was considered worthless if not downright evil. The swamps were filled to make room for housing developments, industrial parks, shopping centers and increased agricultural acreage.
At the same time, the swamps that weren't filled were slathered with DDT to eliminate nasty bugs, mainly mosquitoes. The pesticides, working their way through the food chain, caused eggshell thinning among many birds, most notably the big raptors at the top of the chain—bald eagles, peregrine falcons and ospreys. "In retrospect," says Dr. Robert Smith of the Fish and Wildlife Service's Office of Migratory Bird Management, "an eggshell-thinning problem may have occurred among black ducks, too, but we weren't looking for it so we didn't see it. Eagles and peregrines have come back strongly since the DDT ban in the early 1970s, so there's no reason to think it's still a problem with blacks. Still, we're continuing to lose 1.5 to 2 percent of the population each year."
Nonetheless, the double-barreled blast—swamp destruction and pesticides—sent the black duck reeling into a downward population spiral. Simultaneously, its cousin the mallard was expanding its range and, more important, adjusting to the proximity of people. Mallards will eat nearly anything, and they are as much at home in New York City's Central Park as on a wild marsh, scarfing hot-dog buns or sludge worms with equal rapacity.