Every hunter has come in empty-handed from the field only to hear that maddening refrain, "You should have been here yesterday."

Yesterday, when you couldn't get off work, the ducks flew low and slow, the rabbits ran riot and everybody checked in a deer. The hunter who has to plan his days afield weeks or months ahead is bound to be often disappointed, since game animals don't read calendars.

"You should have been here yesterday," Randy Lewis said in September, when the harvest moon high tide flooded his marina in Wachapreague, Va. "The tide was up in the town and the marsh hens (king and clapper rails) were standing around the dock. I took three gunners out one after another, but we never got to where I wanted to go because they filled their limits (15 birds) before I could work up a sweat with the pole."

Rails are perhaps the most common birds in the mid-Atlantic marshes, especially during the fall when the local birds are reinforced by northern migrants. Being shy and superbly adapted to hiding in and running through the grass, they are seldom seen and nearly impossible to flush. A sharp-eyed marsh walker will occasionally be able to reach down and pick up one as the grass-colored bird crouches at his feet, but under ordinary conditions a rail hunter is going to reap little but fatigue and frustration.

All this changes when abnormal tides drown the marsh, forcing the rails to gather in the high spots or even along the shore. Then the gunners go out in shallow-draft skiffs that skim over the flooded flats, taking turns poling from the stern (hunting under power is illegal) and shooting from the bow. Since rails are not strong flyers, it can be too easy to be sporting.

Or so Lewis and others kept telling me during the four years I kept missing marsh hen tides by a couple of days or a couple of hours. When the September flood was filling game bags in Wachapreague I was in nearby Chincoteague, where a contrary wind "blew down" the harvest moon springtide.

"Well, it happens like that," Lewis said. "A full moon by itself just won't do it.I hope the hunter's moon tide in October will be a good one, because it's likely to be the last change for this marsh hen season."

The weather map looked promising as the moon waxed, and two days before it came full a northwest wind began to blow. A northeaster would have been better, but, "It looks like the tide's going to make," Lewis said as we set off on a dark, blowy Wednesday morning.

By the time we had crossed the bay from Waachapreague to Parramore Island the tide was higher than I ever seen on the Virginia Peninsula. But Lewis was not impressed. "Maybe tomorrow will be better," he said as he shut down the motor and got out his pole. "The moon lacks a shade of being full. But we may kick up a bird or two anyway. You'd better load up."

I had barely finished stuffing in the shells when a pair of birds came up from apparently empty water right under the bow. They seemed too big for marsh hens and whipped away downwind more like teal than rails.

"Oh," Lewis said, leaning on his pole. "I didn't know this was a birdwatching expedition. I was under the impression you wanted to shoot marsh hens, on account of how good they taste and all."

"Those were marsh hens? I thought they were herons."

"King rails," he said. "They run a lot bigger than the clappers. They more or less stick to fresh water except when they're migrating."

A few minutes later, straining to keep the sharply rising wind from spinning the boat, Lewis grunted, "Get ready. There's a bunch of them in that patch of grass to the left."

I didn't see anything but grass and water until a half-dozen birds materialized 20 yards away, flapping wildly into the air toward all points of the compass. Three shots later all of them were gone, unscathed.

Before Lewis could comment or I could reload another three flew up from the same spot; as I stuffed in the shells a straggler took wing from six feet away; my third shot was as far behind him as the first tow, but just as I fired he flared into the wind and was blown back into the shot pattern. "My, you city boys shoot funny," Lewis said. "Down here we try to shoot ahead of the birds."

Scudding downwind, the boat flushed dozens of rails in the next five minutes, leaving the visitor with an overheated gun barrel, a box of empty shells and three birds in the bag.

"I was going to suggest that you pick your shots, so as not to fill your limit too fast," Lewis said. "But never mind; you seem to be enjoying yourself."

I was, and after getting used to the abundance of birds began to hit them. Both our limits were filled by 9 o'clock, which was just as well, because the wind began to gust too fiercely for such a small boat.

The following day brought much the same tide but much more wind, so stiff that Lewis often had to abandon his pole and retrieve birds on foot.

With limits in hand we had to take shelter on Parramore until the blow slackened, and even so the trip back to the dock was a wet one. The discomfort was something of a relief, because bagging the birds had been so easy as almost to justify the hunter's weasel word: "Harvesting."

With the moon still full and the wind still boosting the tide, I had thoughts of giving away half my birds (the possessin limit is 30) so we could go out again next day. "You'd better hold off," Lewis said. "There's such as thing as too much tide."

There was, so much that water swamped cars in the streets of Wachapreague. The Lewises spent the morning securing boats and bailing out their Island House restaurant while marsh hens stood on the windowsills and watched.