Before the shopping malls, before Levittown and Jones Beach, before the traffic jams on the Long Island Expressway, there were the ducks.

In the last half-century, as thousands of homes sprouted and millions of people moved in all around them, the ducks have continued to thrive in the quintessential modern suburbia of Long Island while declining in most other places in North America.

This week, researchers from Ducks Unlimited, Southern Illinois University and other conservation groups are traveling to Long Island to study why the black duck population remains so hardy here.

"As a conservation organization, we are challenged with designing habitat programs to meet the needs of birds," said Tina Yerkes, director of conservation planning in the Great Lakes-Atlantic region for Ducks Unlimited, a wetland protection group of hunters and conservationists. "Without the specific knowledge of those needs, it is difficult to ensure that we are providing not only enough habitat, but the right kinds of habitat."

New York's 20,000 to 40,000 black ducks, three-quarters of them Long Islanders, represent a stable population, one that has withstood development and a rise in aggressive mallard ducks sweeping western and central Canada who steal habitat and mates, said Bryan Swift, game bird unit leader for the New York state Department of Environmental Conservation.

New York's black duck haven isn't accidental. The species declined rapidly from Maine to Florida in the 1950s and 1960s until wetland protection laws and more restrictive duck hunting regulations in the 1970s eased the fall. The population is still estimated to have dropped from 400,000 to nearly 200,000 between 1950 and 1980, Swift said.

But now Long Island's strong conservation programs and abundant food supply attract ducks from as far away as Canada for the winter.

Ducks Unlimited, working with the state and local programs, will trap black ducks, attach radio transmitters and monitor the birds wintering on Long Island. Thirty females will be tracked by truck around Long Island to determine the needs of the ducks in winter and spring for resting and feeding. Researchers will also observe the ducks' behavior and test the food supplies.

The study will be updated on the Ducks Unlimited Web site.

"This study of our local duck population could provide positive proof that our proactive environmental protection policies are improving our entire ecosystem," said Sen. Carl Marcellino, a Long Island Republican and chairman of the chamber's Environmental Conservation Committee.