There is an eerie sound when shots are fired at Canada geese -- the sound of silence.

On Friday, opening day of goose season on Maryland's Eastern Shore, shotgun reports rang across the flat farm fields on a day built for goose hunting. Gray clouds hung low as a cold front moved in. The geese, ignorant of man's hunting calendar and anxious to feed before the storm arrived, swarmed.

In a pit dug in a cornfield near Chestertown, Md., hunting guide Milton Karbaum watched the day break and waited to call to the geese. He grew up with Canadas and speaks the language without benefit of manufactured calls.

"They're on the ponds," Karbaum said, gesturing to the right and left of the pit blind. "They haven't been coming out to feed until about 7:30."

Within minutes the geese began to fly, picking up off the ponds with a rousing chorus of harronks. The guide poked his head through the thatched roof of the pit and answered.

He ran through his litany of goose sounds, starting each in the gravelly base of his throat, cracking his voice yodel-style halfway through the call and winding up on a piercing note that seemed to sustain itself even after he cut it off.

"Gahrrrr-ONK! Gahrrr-ONK!"

The first few flights of geese passed by, uninterested, flying from one pond to the other, cupping their wings when they reached their destination and tumbling down like oak leaves.

Soon Karbaum's exhortations paid off. Ten geese broke off from a larger flock and circled the blind, which was surrounded by silhouette decoys.

The hunters hunkered down while Karbaum called. "Three o'clock," he said. "They're coming in."

The calls of the geese grew louder as they neared until they mingled with Karbaum's imitations in a cacophony of goose noise.

"Take 'em," he said.

Three heads poked through the grassy top of the blind. The guns went off, drowning out all other noises. Two geese fell from the sky and hit with a thud. Then it was silent -- deathly, totally silent.

The sky remained full of geese, large flocks and small, flying high and low, some circling, some pitching, some traveling with a purpose. Geese almost always gabble when they are on the move. Yet for a few strange seconds there was no sound at all but the funereal whoosh of wind over wings, as if the birds were paying homage to the first fallen comrades of another long season.

So begins another 90-day assault on the estimated 800,000 to 1 million Canada geese that will stop this winter on the Eastern Shore. They come here from the far north, lured by the expectation of year-round open water and a groaning board of corn and soybeans left over from sloppy, automated harvest techniques.

Last year a record 250,000 Canadas were claimed by Maryland gunners. That mark is unlikely to be topped in 1981-82, according to Larry Hindman, state waterfowl project manager.

"We certainly won't have the hunting season we had last year because we didn't have the production of young," Hindman said. The 1980-81 crop was notable for high numbers of juvenile birds that came south after an excellent nesting season. Juveniles are traditionally the least wary and most susceptible to gunning pressure.

This year, early indications are that the goose population is weighted in favor of more mature birds. "We had people checking the birds on the first two days," Hindman said, "and we had reports of as few as two birds in every dozen being young of the year."

He said hunting success generally was spotty, and agreed with the observations of some hunters that the preponderance of birds seemed to be in the northern counties, with far fewer in areas south of the Bay Bridge.

There was no shortage in the fields around Karbaum's blind. He works for Bill Price, a goose-hunting entrepreneur who leases some 23 fields around Chestertown and employs a number of guides to call in the birds. On Pond View Farm, where Kent Merkle and I and a third gunner shared the pit blind with Karbaum, literally thousands of Canadas were resting in the two ponds, particularly in a large one that farm owner Allie Messer kept as a sanctuary, off-limits to hunters.

"He won't hunt the inner circle around the pond," Karbaum said. As a result, the geese use the pond as a refuge and good hunting is likely in blinds around the periphery of the inner circle.

It paid off opening day, when Merkle and I and the third man in our party hiked out with a limit of nine Canadas by 8:30 in the morning.

As we left, we watched Messer hurrying a new trio of gunners into Karbaum's blind so they could get their limits, as well.