A few weeks ago a high offical in the Maryland Department of Natural Resources rushed into an aide's office in a dither. "You're going to have to cover for me. There's an emergency."

"What's the trouble?" asked the assistant.

"The Eastern Shore is under attack," said the official. "By geese."

For the last couple of years hunters at Trappe and Centreville and Chestertown, Rock Hall and Cambridge, along the Miles and Tred Avon rivers and elsewhere in goose country have been grumbling and moaning because they never were under attack. There were geese aplenty to look at but the big, graceful birds always seemed too smart to drop into shotgun range.

Cold days passed without a shot fired. The weather always seemed wrong. Professional guides ran out of jokes to tell and worried about running out of business. Weekend hunters considered dropping the hunting rights on farms they leased.

"Last year was not fun," said Ruff Fant, a Washington lawyer who has spent time in the goose blinds. "I began not to like goose hunting for a lot of reasons -- that it was too mechanical, too much a rich man's sport, not really outdoorsy enough. But this year I've enjoyed it much more. I think that the real reason for the change is that last year we didn't kill any geese."

This year the tables have turned just about everywhere on the shore that Canadas are hunted.

On Friday, the last day of the first half of the 1980 goose season, the birds didn't fly all morning on the Corsica River near Centreville. They chose not to move around in a thick fog that hung over the slick calm water.

"We will get shooting," Dave Henderson said matter of factly, "just as soon as the visibility improves."

An hour after noon a gentle, cool breeze pushed the mist out of the river and the flight formations began sweeping overhead. Henderson hunkered up against the wall of the blind and tooted on his goose call. His partner, Steve Boynton, did too. They are not professional callers nor professional goose hunters but the decoys looked good in the water off the point and the calls eventually had the desired effect.

Two birds broke off from a large flock. They swung away and over the blind, eyeing the setup cautiously. They flew off. Boynton and Henderson tooted loud and vehemently. The pair turned, locked their wings and glided toward the decoys, the most wonderful sight in all waterfowl hunting. "Careful now," someone said, "they're coming in."

The great gray-breasted birds soared within 30 yards of the blind before the hunters jumped up and shots rang. The scene was repeated a half-dozen times more before the afternoon flights ended.

"It would never have happened last year," Henderson said. In 1979 the members of his Fort Point Hunt Club finished the season with about 50 geese. This year, in the five weeks of the first half of the season alone, they've taken home 218.

Why the change?

"Our November count shows the second-highest goose populations ever in the state," said Tom Cofield of the Maryland Wildlife Adminstration. The figures indicate 31.8 percent more Canada geese this year than last. The count list 644,500 wintering Canadas, with the huge majority on the Eastern Shore. The highest November count ever was 661,000 in 1975. Those figures are used only for comparison, and are in fact well below the actual numbers of wintering Canadas.

Cofield said the increase resulted from favorable nesting conditions in eastern Canada, where the geese reproduce, and a high proportion of geese of breeding age within the population that went north last spring.

The result is a massive population with a large number of juvenile birds. Goose hunters love juvenile birds because they are not as wary as their older counterparts and are much more willing to come to decoys. The juveniles have made this a year that Eastern Shore goose hunters will be sighing over for decades to come.

"Last time I was down," said Jack Jagoda, a member of the Fort Point Club, "we took six geese to the pickers to be plucked. By the time we arrived there were already 300 geese ahead of ours."

There are no figures available yet on the goose kill for the first half of the season. "We haven't got a count yet," said Cofield, "but the gabble around the office among the guys who go is simple -- fantastic hunting."

He'll get no argument from Henderson, Boynton and Jagoda and the other members of the Fort Point Hunt Club, or from Fant or Randy and Perry Hollins, who lease some land near Oxford; or from Frank Gomme, who is enjoying his best year in the cornfields near the Blackwater Wildlife Refuge, or from Jim Bugg who hunts at the mouth of the Choptank River, or from Dave Powell and Jim Crumley, who do some guiding down by Trappe.

They're all walking around with big grins; grins they've waited awhile to wear.

Maryland's wintering Canada geese now get a chance to relax as the hunting season remains closed through Dec. 9 on the Eastern Shore and Dec. 11 west of the Chesapeake Bay. The lions's share of the season then begins, running through Jan. 31 on the Eastern Shore and Jan. 20 to the west.

Traditionally the hunting emphasis in the second half shifts from water blinds, where the geese are intercepted on their way to resting places in the rivers, to blinds in corn fields where they come to feed, driven by an increased need for body fuel as temperatures decline.