There are something like 16 species in the subfamily Anatinae that show up regularly in the waterfowler's bag, but face it, when somebody says "duck," we think "mallard." This isn't to say that hunters aren't pleased to welcome a flock of teal or wigeon or an occasional black duck into the decoys, but the morning that ends with a limit of greenheads is just a bit brighter.

It wasn't always so. Back when the waterfowl market was still legal, the going rate for ducks reflected a different hierarchy. The menu at Baltimore's Rennert Hotel was typical--the going rate for a mallard was $1.50; the price for a canvasback was $3. J.C. Jackson, a Baltimore wholesaler who specialized in poultry and waterfowl, paid up to $7 for a brace of cans fattened on wild celery in Chesapeake Bay.

Sportsmen of the era held the can in the highest regard. On a January hunt in 1900, outdoorsman and naturalist George Bird Grinnell visited Currituck Sound for a few days of shooting. A few weeks later, he wrote: "I have recently had the opportunity of being brought into what I may call close association with the greatest of all the wildfowl, the superb canvas-back duck."

The change in loyalties between Grinnell's time and ours was probably a simple matter of numbers. Most North American ducks suffered major declines in the late nineteenth and early 20th centuries as marshes were filled, drained, and polluted, but the canvasback seemed to have been particularly vulnerable. In the late 1930s, when most ducks rebounded, thanks to restrictive hunting regulations and the first efforts to set aside habitat, the canvasback failed to respond.

The old timers in the Atlantic and Mississippi flyways knew that cans doted on wild celery during the fall and winter; in fact, when the ornithologist Alexander Wilson proposed the first scientific name for the species in 1814, he dubbed it "Anas valisneria," Latin for "wild celery duck." At the turn of the last century, wild celery or eelgrass was a canvasback staple across the eastern third of the continent. Sadly, the great beds of wild celery didn't thrive in the conditions that came with the 20th century.

Some observers were convinced that a disease attacked the plants; others thought that incursions of salt water from canals caused the decline. Silt from widespread sheet erosion may have changed the bottoms of many marshes, discouraging the celery. Exotic plants like Eurasian milfoil and Hydrilla may have out-competed the native plant in some situations, and burgeoning schools of carp may have rooted out many stands.

Whatever the causes of the decline in wild celery, the result was the same. In 1947, a duck hunter on the Eastern Shore of Virginia wrote that local creeks once "fairly swarmed with canvasback, redhead, scaup, blackduck, Canada geese, brant, and swan.

But with the eelgrass went the ducks." Two years later, a Minnesota hunter wrote with nostalgia that "the celery brought the canvasback. Heron Lake was one of the greatest canvasback concentration points in the country. . . . By 1922, the celery vanished. The Canvasback have never returned in numbers."