At Blackwater National Wildlife Refuge on Maryland's Eastern Shore, naturalists have charted the rise of the Canada goose for a half-century. They watched its numbers leap from 5,000 in the late 1940s to the peak period a decade ago when 80,000 swept in one November. Now refuge manager Don Perkuchin is watching their decline.

"There has been a steady decline over the last 10 years," Perkuchin said.

In the last three years alone, the estimated population of Canada geese wintering at Blackwater dropped from 32,000 during one week in October 1984, to 18,000 during one week this month

And the problem isn't restricted to just the Blackwater preserve, which covers 16,000 acres. Biologists in the entire Chesapeake Bay region are concerned about the future of the geese, particularly in Maryland, which has established itself, with an average of almost 500,000 birds wintering here, as the Canada goose capital of the country. But the Maryland Department of Natural Resources reported 377,400 geese in its midwinter survey this year, the lowest count in 20 years.

What experts are quick to point out, though, is that the Canada goose population in the United States as a whole is strong -- so strong that the geese are becoming a nuisance in some areas, damaging crops and destroying golf courses.

What is happening in the mid-Atlantic flyway, the Maine-to-Florida path that millions of birds follow during migration twice a year, is "inequitable distribution of the geese," said Matt Perry, a waterfowl biologist at the Patuxent Wildlife Refuge.

"There has been a slow movement of wintering grounds north over the last 20 or 30 years," he said. For instance, North Carolina was once the winter home of the majority of Canada geese on the continent. Today, only a few thousand geese travel that far south.

Many of the factors that caused the decrease in the Canada goose population in North Carolina also have contributed to its decline in Maryland, where biologists disagree about which factor has had the greatest effect. Some say plentiful feeding grounds and mild winters have caused the birds to remain in northern states. Others say hunting pressure has been so severe in Maryland that flocks are moving inland. Still others argue that a shortage of sanctuary areas exists, and that vital shoreline habitats have been destroyed by development.

Whatever the reasons for the decline, Marylanders want the geese back. In a state that reaps $40 million annually during the hunting season, geese are "big business," said Larry Hindman, program manager for Maryland's Department of Natural Resources. Hence the geese have wound up in the center of a politically charged debate.

During the course of the year, hundreds of bird watchers and hunters flock to the Eastern Shore for the geese. So thousands of Maryland residents and whole towns in Eastern Shore counties would lose a tremendous source of income if the geese relocated altogether. Wildfowl hunting "is an economic shot in the arm for the Eastern Shore," Hindman said. "Whenever we take restrictive measures we hear from the hunting guides, the hotel and restaurant owners, and of course, the hunters."

To appease the conservationists and those involved in the hunting industry, the Department of Natural Resources reduced the number of hunting days last year from 90 to 70, and delayed the opening of the season by two weeks to give the early arrivals, breeding birds and younger geese, a chance to find a safe habitat. "Using this strategy," Hindman said, "we should see an increase of 112 percent over last year."

But Patuxent's Perry thinks that the long hunting seasons of the last decade may have taken a serious toll on the geese that might not be reversed so quickly. "The hunting is so great we are at a breaking point. If a flock is looking for food and a few get blasted by hunters and the rest can't find a place to feed, then they go somewhere else," he said. "The hunters have overdone it, and now they're paying for it."

Maryland has about 50,000 registered hunters, Hindman said.

Currently, many groups are acting to preserve waterfowl in the region. Groups are studying banding the birds to observe their migratory patterns and the causes of the population shift. And there are private conservation organizations, such as the Wildfowl Trust of America and Chesapeake Wildlife Heritage, which, in addition to state agencies, are developing long-term habitat management, breeding and educational programs geared toward keeping Canada's summer geese in Maryland for the winter.

MIGRATION

Every fall, vast flocks of Canada geese fly back to the Chesapeake Bay region from their summer nesting grounds on the Ungava Peninsula in northern Quebec, a distance of about 1,500 miles. They begin to arrive in late September and reach peak concentrations by late November.

CHARACTERISTICS

Canada geese are most widely distributed and most well-known of our wild waterfowl. They can be seen from the Atlantic to the Pacific, from the Gulf of Mexico almost to the Arctic Ocean at some season of the year. The male is usually larger and has a deeper call. Geese weigh six to 15 pounds with a wingspread of five to more than six feet. They often live 20 to 40 years in captivity, but wild birds probably average five to 10 years.

SENTINELS

Keen of sight and hearing, geese are difficult to approach. When feeding on water or land, two or more black necks are stretched upward on lookout for danger. A warning from a sentry and the flock flies away.

FEEDING

Geese feed on shoots and roots of aquatic plants in the marshes and on green browse and grain in the fields. Eastern Shore farmers are planting less corn and more soybeans, which is not a good goose food. Adults need about a half-pound of food a day; less in warm weather and more during cold periods and long flights. If hunted extensively during the day, they will feed at night by moonlight.

IN EXTREME COLD

And wind geese will sit out the weather and not eat. They save energy by not flying. To stay warm they tuck bills and feet in their soft down feathers. Goose down is incredibly light, effective insulation.

SHORT STOPPING

Canadas tend to migrate only as far as they must to find food and water. Every year some Canadas are staying farther north in winter.