It was an awful morning after a great party. Nimrod, who never in his life had summoned the nerve to go on even one blind date, woke up dimly aware that he had invited an utter stranger to go goose-gunning.

Dinner and a movie with someone who turns out to be totally incompatible can't begin to compare with the agony of finding yourself stuck in a waterfowling blind with a person you wish would go away.

A day in a blind begins before dawn and more often than not drags on toward dusks. If the weather's good the shooting is likely to be bad and vice-versa, so that on a typical day one winds up either frozen or frustrated. Minor mannerisms such as tooth-sucking or finger-tapping can become infuriating when you stand cheek by jowl for hours on end; a friendship that has endured through several seasons of waterfowling has passed a test almost as tough as marriage.

There are deeper difficulties. Nimrod is one of those who, as philosopher Ortega y Cassett said, "do not hunt for the killing but kill to justify the hunting." From time to time he has found himself the unwilling partner of people who do not share that view: scorekeepers, who regard live birds as little more than challenging targets; macho boobs, concerned only with blowing away more geese or ducks than anybody else; and, once, a creep who laughed at crippled birds.

Most of what he knows about waterfowl and waterfowling he has learned from guide Cork McGee of Chincoteague, who has loved, studied and hunted the birds and beasts of those rich marshes all of his life. McGee chooses his clients carefully, and not the least of Nimrod's worries was whether guide and stranger would hit it off.

After a few hours in the blind Nimrod began to suspect that he had misjudged the stranger, and by lunchtime he was sure of it. She and McGee had so cottoned to each other that he could barely get in a word.

For one thing, McGee has heard all of Nimrod's stories two or three times, and anyway they don't hold a candle to those of the Yankee Princess, as Nimrod had come to think of her. Tales of stalking moose and elk; of skiing out West and climbing in Nepal; of duck-hunting off the New England coast in such a sleetstorm that the gunners had to chip themselves out of the ice when it was time to head in.

They waxed particularly warm on the weird clients a guide comes across, for, as Nimrod blushed to learn, this nice lady oil executive who listened so attentively to his advice had served as a waterfowling guide long before he ever laid hands on a shotgun. She got the normally spare-spoken McGee going he was telling stories he never had told Nimrod.

She knew how to blow a goose call, and when not to. Nimrod has a whole bunch of goose calls at home and, at McGee's suggestion, leaves them there. She could pick up incoming birds quicker than Nimrod, who is blessed with phenomenal sight. In the space of a day she learned to distinguish distant black ducks from gadwalls, which is more than McGee has been able to teach Nimrod in six years. Using a strange shotgun that didn't fit her, she could bring down geese, although she refused to claim any of the birds until the other two held their fire as one flight came in and a goose fell anyway.

Best of all, she loved the marsh. McGee loves the marsh so much that often, after six straight days of guiding, he will take his wife out there on Sunday just to watch the birds. Nimrod has almost come to think of a day's hunting there as a day on the marsh, with anything brought home simply a bonus. h

But he'd grown so familiar with the marsh his eye had dulled, and much of the delight of the day was seeing it afresh through the eyes of the Yankee Princess. And it was good that she appreciated it, for most of the first day and much of the second were spent watching birds McGee had called in being shortstopped by gunners in nearby blinds sited by a rival guide for just that purpose. Time and again gesse "blared off," as McGee puts it, when the other gunners fired before the birds came into anyone's range.

McGee got as mad as Nimrod, back at the motel, got into an argument with the skybusters. The Yankee Princess got everybody calmed down and sitting around a dinner table, so that next day the gunning was more gentlemanly, and everyone took home plenty of birds.

The utter stranger had turned out to be a perfect one.