We had looked at the calender and the tide tables and decided the last weekend was the weekend to hunt rail birds in the marshes of Virginia's Eastern Shore.

The full moon promised spring tides, which are necessary for poling a tippy skiff through the striff grass in pursuit of the common but wary "marsh hens," as watermen collectively term Virginia, clapper, sora and king rails. The early season promised fine, slightly brisk weather for the poling, which can be brutal in heat and cruel in cold.

"You can fool with tables and calenders all you like," said Randy Lewis of the Wachapreague Marina. "Best thing is to wait for a northeaster and then come down. You can pole yourself to death and never see a bird if the conditions arean't right."

Lewis knowns the magnificent marsh behind Virginia's barrier islands as well as any man except perhaps his father, and gives good advice. But city boys who live five hours inland and have more-or-less-regular jobs have to schedule things.

Well, the wind was wrong except when it wasn't there, and the tide didn't "make." The waster in the grassy flats was too shallow to permit the rapid poling that makes the birds flush rather than swim away or hunker donw. The first day, one of the gunners fired one shot and got one clapper rail. The second day, the other got a shot and one king rail. That was just 108 birds under the legal limit for two men over two days.

The other hunters had similar luck, and went away muttering. We had a memorable weekend, once we let go of our unworkable plans and just took what the marsh was offering at the moment. The fallback position after the first day's rail hunt had been dove shooting. The Delmarva Peninsula is covered with cornfields and drenched in dovers - except this fall. We gave that up after scouting a dozen doveless fields and finally running into a convoy of dove-seekers who had been working their way south for 30 miles without seeing a bird.

"Well, gasharootie," my friend said, kicking idly at a lump on the edge of the marsh where we had wandered wondering what to do. The lump turned out to be an oyster, Rinsed in the ebbing tide and teased open with a Barlow knife, it was delicious. So were several score of its brethren, which we gathered with a sense of guilt even though we knew we were not poaching.After all these years of buying them we just couldn't get used to picking them up off the ground.

We sat there shucking them and sucking them while the declining sun turned the marsh pink, the shore gold and the nattering seagulls black.A final grace note was the oyster-eating cat that wandered over the sat companionably down with us until every last shell was licked dry.

The following day, a Sunday and therefore huntless, we had planned to spend fishing. But nothing was interested in what we were offering, so we pottered around and had a splendid time trespassing on the Nature Conservancy's islands. The day wa hot and still, and about the time we were going to give up because of sunburn and thirst another boat came alongside and pressed cold reviving beer on us.

Bad navigation and a bad chart led us into the wrong channel shortly after that, and we came across three boatloads of people slipping and sliding over a mudflat, staring at the ground as though in search of the keys.

We stopped to see what the hell, perhaps lend a hand. As we stepped ashore our bare feet sank knee-deep in the mud, except where there wre clams. There were clams everywhere, and in half an hour we had all we could carry. When we got back to dock, fishless, we pulled the crab pots we had set out that morning and they were crammed with fierce and tasty blues.

Next day's hunt was more of the same. Two hours of gut-wrenching poling put up, at last, one rail. Searching the submerged grass where it fell, we found a diamondback terrapin, and then another and another, enough for a great pot of one of the world's most succulent soups. Where there were no terrapins there were more crabs, and on every blade of grass were two or three big periwinkles.

Surveying our weekend's "bag," we realized that if we had had a "successful" rail hunt we would have had to buy another cooler to haul them home in.