The snow showers were racing us to the river.

We had spent a wonderful morning at the Blackwater National Wildlife Refuge near Cambridge, MD, viewing thousands of geese, swans and ducks along with the refuge's amazing array of bald eagles. Not satisfied with this abundance, I wanted to add more Bay ducks to our viewing bounty. We were headed to Cambridge to see the winter ducks that congregate there along the Choptank River.

The snow had just started, but we could see the darkening clouds and their snow showers bearing down on us as we turned onto Oakley Street , where we slid to a stop along the curb. The Choptank sluiced under the jersey barrier at the end of the block.

The snow was quickening as we hopped out, binoculars in gloved hands. Before us were rafts of gorgeous ducks bobbing on the wind-swept waters. American wigeons stretched from the wide lawn on our right down to the shoreline and out into the river.

I glanced up. The opposite shore, more than a mile away, was lost in the snow. We could still see the ducks in the middle of the broad, tidal river. There we could just make out the big white spots on the black heads of the buffleheads and the picturesque black-and-white patterns of a few long-tailed ducks.

Just a few feet away, though, sloshing alongside the jersey barrier, was the real object of our pursuit: scores of canvasback ducks. The raft included a handful of redheads and scaup as well. This was a real bonanza.

In the splendid world of waterfowl, the canvasback (Aythya valisineria) has somehow managed to win my heart like no other.

The chestnut head with its ruby eyes slopes elegantly down to the dark gray bill. A black breast and a black tail that extends up onto the lower back serve as perfect bookends to the brilliant white sides, visible just above the water line. The drake's canvas wings and back give the bird its name. Underneath, his wings and body are white. The female canvasback shares the male's elegant lines, but the colors are subdued. The head and breast are light brown. The back and tail are a pale gray. Like the males, hens are white underneath. Immature birds and nonbreeding males resemble females.

The gathering storm obliterated the midriver birds, forcing us to focus on the canvasbacks, which were just a few feet away. These are big ducks, about 20 inches long and 2.5-3 pounds; we didn't need binoculars to see every detail. They were clustering together along the shoreline because of the storm, and watching them through the wet snowfall was hypnotizing.

While most birds enter their breeding plumage in the spring and raise their broods in the summer, ducks put on their colorful breeding feathers, which ornithologists call their "alternate plumage," in late fall and winter. Here in the Chesapeake region, we get to see the birds at their most colorful during the height of winter. Those handsome colors are essential elements in the establishment of breeding pairs. The engagement will last the entire two to three months that the birds inhabit the Bay.

The birds won't build their nests and have their chicks until early spring. By then, they will have left the Bay for the freshwater lakes, ponds and marshes of Western Canada and down into the United States as far as Wyoming. Oregon and Washington have year-round populations of canvasbacks.

Although most breed in Canada, canvasbacks will winter along both U.S. coasts and the entire southern tier of our states and into Mexico. During the winter, they inhabit either fresh or partially saline waters. The Chesapeake is a favorite spot. The big ducks congregate here in impressive numbers, often in the mixed flocks we witnessed on the Choptank.

Geese and swans have wingspans that are much larger than the birds' lengths. That's not the case with canvasbacks. They flap their relatively short wings rapidly in flight. To take off from the water, they skitter along the surface for a few moments before their frantic wing beats can get them airborne.

Canvasbacks are diving ducks. With quick, almost imperceptible head jerks, they gather themselves for sudden dives below the surface where they propel themselves with their webbed feet. The birds are in search of wild celery, an underwater grass whose Latin name, Vallisneria, is a part of the canvasback's scientific name, albeit in an alternate spelling.

Finally, I needed to be dragged away. The snow squall was upon us.

Life's limitations are inevitable, sometimes coming at us with unrelenting speed. But sometimes, through accidents of timing and luck, those constraints are held at bay just long enough for moments of transcendent joy that lighten our hearts for a lifetime.

The New Year was off to an auspicious start.