With a seriousness befitting his role as the man prosecuting a public official, Assistant U.S. Attorney John W. Sheldon stared at the man on the witness stand and asked, "Do you know how a goose flies?"

Mischief glowed in the wrinkled face of U.S. District Judge R. Dorsey Watkins, who was presiding over the trial of Anne Arundel County Excutive Robert A. Paschal. The judge raised his elbows and flapped the voluminous black folds of his judicial robe.

"Other than by flapping his wings, I mean," the embarrassed Sheldon added.

As Gov. Marvin Mandel was spending last week fighting political corruption charges in the ceremonial first-floor courtroom of the federal courthouse here, Pascal was waging his own battle upstairs, trying to prove that chicken feed wasn't really jailbait.

In a five-day, nonjury trial that frequently set prosecutors, reporters, defendants and the white-haired jurists rocking with laughter, Pascal and three hunting companions contended that they hunting geese in a baited field - had been wrongly accused of a federal offense.

In the first place, they said, the 100 pounds of corn kernels that were scattered in a nearby chicken yard did not quality as goose bait.

Then, even if the corn was considered goose bait, they said, the chicken yard was a full 700 yards from the blind where Pascal and his companions were hidden - too far away to be considered part of the same field.

Last Oct. 30, agents of the U.S. Fish and Wildlife Service arrested Pascal and his hunting buddies - Dominic N. Fornoro, 59, president of the Maryland District of Columbia AFL-CIO, Elmer F. Daubert, Jr., 45, a sporting goods retailer from Pasadena, Calif., and Alfred J. Schultz, a construction superintendent from Hoover - and charged them with hunting in a baited field.

The charge carries a maximum sentence of a $500 and six months in jail.

Joseph W. Ashley, a 61-year-old Kent County farmer who rented his farm to Pascal for the 90-day hunting season, was also arested for allegedly baiting the field. Ashley faces a maximum sentence of $2,000 fine and two years in jail if convicted.

Judge Watkins scheduled his decision for 2 p.m. Monday.

It was Ashley's decision to earn extra money from his farm by raising chickens and selling their eggs that finally pitted him and the Anne Arundel county executive against the federal agents.

"They arrested me for feeding my chickens," Ashley complained in response to questioning by his defense attorney J. Federick Motz.

"Ashley said he scattered two five-gallon buckets of corn as feed for his 300 chickens each day. Sometimes, if the weather is wet, the chickens cannot peck up the kernels and the grain piles up, he said.

An extension poultry specialist with the University of Maryland in Salisbury, James L. Nicholson, testified that 100 heavy breed chickens like Ashley's would eat 40 pounds of corn each day. A five-gallon bucket of corn would weigh 33 pounds he added.

Judge Watkins quickly computed that Ashley's 300 chickens, which should have been fed 120 pounds of corn daily according to Nicholson, were only getting 66 pounds to eat. "Those chickens were underfed," he declared.

At another point today, during his cross examination of one of the Wildlife agents, defense attorney Motz picked up some of the presecution's exhibits and inadvertently turned an envelope of loose corn upside down.

As Motz and prosecuting attorney Sheldon scrambled on their knees to pick the kernels up from the royal blue rug, Judge Watkins dead-panned, "maybe you can bring a goose."

During the course of the trial, a series of agents from the U.S. Fish and Wildlife Service testified that some Canadian geese flying south along the main migratory route spotted the pile of corn in Ashley's chicken yard and came down to eat.

On the first day of goose hunting season, Pascal and his buddies were concealed in a blind in the middle of Ashley's harvested cornfield on the Chester River, waiting for the exact hour and minute of the season opening, so they could start shooting.

Pascal, an avid hunter who four years ago, paid a fine after admitting that he had hunted in a baited field, testified that this time he was tossing corncobs he found in the blind as far away as possible, to stay within the letter of the law.

Not long after he finished doing this, the federal popped out of their hiding place in the bushes, told him the farm was being closed to hunting because of the corn scattered across the chickenyard, and subsequently arrested him and his companions.