SCILLY SEASON : Nothing much happens on the Isles of Scilly. But that’s exactly the point of visiting a spot reminiscent of rural England generations ago.

For a yuppie couple from Britain’s Midlands, a high point of their week’s stay on the Isles of Scilly, 30 miles off the southwest tip of England, was the whistling concert they heard one night from the parking lot below their hotel window when the Mermaid, the islands’ most popular pub, closed.

“It was really rather interesting,” the woman related in the breakfast room the next morning. “It wasn’t just little tunes they whistled, it was whole songs, all the way through. They started with “Rule Britannia” of course, and then somebody whistled something else. Then people would call for more and someone else would whistle something. I don’t know how they have the muscles to whistle for so long, but it beats fighting--and it sent me right off to sleep, I’ll tell you.”

For a boy on a rented bicycle, it was pumping his way to the top of the road to the 16th-Century Garrison overlooking Hugh Town on St. Mary’s Island. “My whole family is down there, cheering me on,” he volunteered proudly to a passerby, as he gulped for air.

For Petra, a dental nurse in her 20s, the Scillies provided a place to let the stress of a frantically paced London melt away. “In London, people measure time by the second,” she said. “Here they hardly measure it at all. I’m sure the people who live here can see the tension in Londoners’ eyes when they first arrive--before they’ve realized they can relax.”

The Scillies--a compact cluster of dozens of islands, only five of them inhabited, and each of those small enough to be walked easily from one end to the other--look like a chunk of rural England of a couple generations ago, maybe lifted from coastal Cornwall or Devon and flung out into the Atlantic.

Burial artifacts give evidence of prehistoric settlement 1,000 or more years BC, and skimpily recorded history puts Christian monks on the Scillies in the 5th or 6th Centuries AD, when, according to maps they left behind, the islands were a single land mass, not yet eroded by the ocean into their present fragments. Arthurian legend places the idyllic land of Lyonnesse on portions of a Greater Scilly now submerged beneath the sea.

What still remains above water (the highest point is just 160 feet above sea level and geologists give the islands only another 49,500 years before they vanish) constitutes, today, the Isles of Scilly, with patchwork fields covering the leeward sides and moors of tougher vegetation braving those exposed to the ocean winds. Between them are shoals, and waters shallow enough that at some seasons one can walk between the islands at low tide. Standing on a hill on one of the islands one afternoon, a Scillies resident looked at a neighboring island, across two miles of ocean whipped by a breeze into frothy whitecaps. “I walked over to that island once at low tide,” he reminisced. “It was hardly more than thigh deep. But bear in mind, it was March then.”

To understand the Scillies--and to avoid disappointment if you’re put together differently than the people who flock there yearly--it’s important to know what they are not.

They’re not hot, although the people who live there think they are. “Yesterday was a scorcher,” one told me by way of warning the August morning I arrived. It had gotten up to 69, she said with a grimace.

Since it’s not hot, there’s no ocean swimming or sunbathing to speak of. Most of the few people in the water on an August day are hardy children wading, or adults, with nets, shrimping. A woman who complained that she had fallen asleep on the beach and “got sunburned” acknowledged, under questioning, that what had gotten burned was her left ankle--the only part of her otherwise fully dressed body left uncovered against the chill breeze.

Except for a couple of pubs and some hotel bars, there’s virtually no night life. One evening a community theater presented J.B. Priestley’s “An Inspector Calls,” and other nights there were slide lectures on local birds, flowers and shipwrecks. On a Sunday night, I walked the six-block length of the main street of Hugh Town, the Scillies’ only commercial center, without seeing or hearing a moving vehicle.

And it’s definitely not a jet-set destination. Access to the Scillies from London is by train or car to Penzance, the closest city on the English mainland, and then a 20-minute helicopter ride or three-hour ferry trip. The biggest of the islands’ 10 hotels has only 40 rooms, and most are much smaller. When former Prime Minister Harold Wilson, who has a modest house on St. Mary’s, and Prince Charles, who, with his family, stays on privately owned Tresco Island, come to the Scillies, it’s to escape clamor, not to cause it.

What does a visitor do then on the Scillies? Well, the chief pastime, it seems, is simply moving about and coming to a stop when necessary, to rest, eat lunch or refuel at a pub and, later, to indulge in calorie-laden pastries with clotted cream at a tea garden. This moving about can be walking or biking the miles of paths--up and down hills covered with gorse and heather, through fields of flowers, along rocky coasts and sandy beaches. Or it could be taking a 15-minute boat ride to one of the other islands and then walking or biking it, exploring its coves and fields and examining its ruins. And on Friday nights there’s the big social event of the week: gathering on the quay or in boats to watch Scillies’ boatmen race six-oared gigs, some of them more than a century old, between the islands.

This low-key formula packs them in on the Scillies, it turns out. Most of the hotels and guest houses are booked up well before summer (many people reserve for the following year at the same time they check out) and the islands, which have a resident population of only 2,000, are at their carefully controlled tourist capacity for much of the spring and summer. “What brings you all the way out here?” Tony, the headwaiter at Tregarthen’s Hotel, asked me at breakfast my first morning. “You’re an American, aren’t you?” Unmasked at the start. So much for trying to blend in.

“Do many Americans come here?” I asked. I hadn’t seen any, nor, it turned out, did I in the remainder of my stay.

“Not many,” he said, “but a few have recently. One of your big newspapers did an article on us and that might have started it.”

Was it a good article?

“Oh, mostly, there was nothing really wrong--but they do have to be a bit artistic, don’t they?”

I wasn’t artistic enough to come up with a good reason for being there, other than that I’d wanted someplace pleasant that I’d never visited, to relax for a few days and look at English birds. The Scillies are famed in British birding circles as a place to see rarities, but the time for seeing them is October and the rarities are usually North American birds that have been blown off course and wind up in the Scillies as their first landfall. In October, the placid pace of life in the Scillies is ruptured by the presence of 200 or more “twitchers,” as the British call birders who maniacally chase rarities, darting from island to island.

When I wrote birding friends in England to ask recommendations for staying in the Scillies in August, I received anguished pleas that I change my plans. I’d see nothing then but English birds, they warned. There’s nothing happening in the Scillies in August, it would be dead quiet, they implored. It sounded ideal.

Resigned to my going in the wrong season, the friends gave me some helpful advice: Allow time in my travel connections for possible delays due to fog or wind; stay at Tregarthen’s Hotel (and make contact with Will Wagstaff, a top-notch birder and botanist who is field officer for the Isles of Scilly Environmental Trust, which administers the public lands of the islands and promotes conservation.

I treated myself to the overnight sleeper from London’s Paddington Station to Penzance, although there also are several daytime trains that make the trip in about five hours. In Penzance, hungry from my trip, I spotted the Baker Boy’s Oven Door and promptly was overwhelmed by my first brush with Cornish pastry. There, in two big show windows, were 52 (I counted them) different kinds of pastries, with such baffling names as “tiger baps,” “granary bloomers,” “white twinnies” and “long white unders.” I grabbed a meat-stuffed “Cornish pasty” (pronounced PASS-tee), took a shuttle bus to the heliport a mile away and boarded the 32-passenger Sikorsky S61 helicopter that makes the quick flight to the Scillies several times a day, weather permitting, for a fare of $60.

From an altitude of 1,000 feet, I had stunning views of Cornwall’s jigsaw-patterned fields, then the promontory of Land’s End, and, after a brief expanse of ocean in which I was close enough to see gannets and shearwaters crisscrossing at water level, I was over the rocky southeast coast of St. Mary’s, the largest of the Scillies, and dropping softly onto the grassy landing field.

Minutes later, I was at Tregarthen’s, surveying the quiet garden where, a discreet plaque said, Alfred Lord Tennyson, a regular guest in the hotel’s early days, spent long hours writing “Enoch Arden.” The view--the long stone quay and the harbor, crowded with dinghies and small sailboats--probably hadn’t changed much in the intervening century, but since I had only five days, I didn’t let it inspire me to write an epic poem and instead headed out to tramp the island.

I walked through Hugh Town, situated at a point where the island is squeezed together like an hourglass, with beaches facing the sea on either side, just three blocks apart. Sooner than I expected, I was out of town, past a pottery shop and a stately house named Nowhere and onto the Lower Moor.

Everywhere I looked, I could see people in motion--walking or biking, singly or in family groups, silently plodding with canes and butterfly nets, or chatting--or, in the case of many of the children, polishing their debating skills. “Pick it up, Tobin, pick it up like a nice little girl,” I heard a mother implore from somewhere on the other side of a hedgerow. “I shan’t,” came the small-voiced but firm answer. “Colin,” I heard from a father-voice behind me, “you mustn’t keep doing that. You really mustn’t keep sitting down.” “And you really mustn’t keep kicking me,” in measured response.

I turned onto a rocky nature trail and met an elderly woman leaning on a walking stick. “Bit rough going here, isn’t it,” she observed. “Yes, but at least there’s a nice cool breeze,” I said, having just rolled down my shirt-sleeves. “Not here,” she said, looking at me as though uncertain whether I’d tried to make a joke. “It’s really rather hot.”

By nightfall, I was back in my room, resting my aching feet and savoring the memory of the first of five sumptuous four-course meals I was to enjoy at the hotel, as well as an entertaining slide lecture by Wagstaff on the natural attractions of the Scillies. Then I began boning up on the “off-islands” (the catch-all term for those that aren’t St. Mary’s) in preparation for the one daily ritual that produces crowds on the Scillies: the morning gathering on the quay to board the boats that transport visitors to Tresco, St. Martin’s, St. Agnes, Bryher or Samson.

Tresco is the jewel of the Scillies. It contains, on its 1-by-2-mile expanse of wooded hills and rolling moors, the islands’ most interesting ruins--a 12th-Century Benedictine abbey and castles and fortifications from the 16th and 17th Centuries--and the Abbey Gardens, which contain native plants and flowers as well as hundreds of subtropical varieties gathered over the past two centuries from around the world. Tresco is the only island in private hands, the descendants of Augustus Smith, who was given a lease to the island by the Duchy of Cornwall in 1834.

As I walked a roadway on Tresco, a resident pointed out an aristocratic-looking gentleman driving by in a three-wheeled cart, the only kind of motor vehicle allowed on Tresco. It was Robert Dorrien Smith, the island’s current lease-holder and resident of Tresco Abbey, not really an abbey but an imposing manor house built in 1843 near the original abbey’s ruins.

To get to Tresco, I joined the crowd on the quay at St. Mary’s about 9 a.m. and scanned a blackboard that lists the boats and their destinations for the day.

I joined 85 people and two dogs, squeezed onto every bit of horizontal space on a broad, open motorized boat called the Britannia. The docking sites on all the islands vary according to tides and, after a placid 15-minute voyage across a couple miles of flat sea, we landed at Cairn Near, on the southern tip of Tresco, the dock used at low tide.

With Wagstaff pointing out plants and birds and guiding us through a meandering network of trails, our group of a dozen walked the island. We studied the birds at two wooded ponds and found, in addition to the expected swans, herons and ducks, two very unexpected visitors from far away that would have excited even those British birding friends who shun the islands until October. They were a citrine wagtail, a pipit-like bird of Siberia and a semipalmated sandpiper, a shorebird common in the United States but rarely seen in Europe.

We climbed a hill to see the gutted exterior of the Blockhouse, a stone fortification built in the 1500s and destroyed in the civil war in 1651 by supporters of Oliver Cromwell. To the north were the ruins of Cromwell’s Castle, built in 1651, and King Charles’ Castle, a century older.

Lunch at Tresco’s only pub was Cornish pasties and ploughman’s platters (salad of lettuce, cucumbers, beets and onions; two huge wedges of white Cheddar cheese, size depending on the cook’s generosity; two generous slabs of coarse, fresh bread; dollops of mayonnaise and sour cream and a mound of pickle relish in a piquant brown sauce). For some of us, it was all washed down by a pint of aleand, for a hardy few, dessert followed.

“You should have been there one day last year,” a woman at the next table said to me at supper back in the hotel that night when she heard me say I’d spent a quiet day on Tresco. “Police everywhere. They were dropping in by helicopter. A man had dug up some human bones and they thought somebody had been murdered. What a commotion. Then I heard on the telly later that it turned out the bones were more than a thousand years old. But I suppose it still could have been a murder.”

Friday night--gig race night--I sat with a group in Tregarthen’s lounge, peering through the big picture window that usually provides a panoramic view of the harbor and the quay, the finish line for the St. Martin’s-to-St. Mary’s race that was supposed to be underway. But what we were looking at was an impenetrable fog that had rolled in while we ate, swallowing up the harbor, the spectator boats lined up at the finish line, the quay where hundreds more had gathered to watch, and most of the 200 yards of hillside between us and whatever action there was down below.

This prompted a round of storms- from- hell- that- really- screwed- things- up- for- visitors- to- the- Scillies stories from the regulars, amusing to them but enough to raise the consternation level of at least this visitor, with a nonrefundable ticket back to the States a few days hence.

There was the 1967 storm that broke up the Torrey Canyon on a reef just eight miles off the Scillies and loosed what was then a record oil spill. Although most of the oil washed eastward, away from the islands, some Scillies hotels still have mats in front of their doors that, instead of wishing “Welcome” inquire politely, “Tar?”

And there was the 1979 “Fastnet disaster,” when a sudden storm exploded on a world-class yacht race as it passed the Scillies and, for days after, de-masted yachts were being dragged into the harbor, one of them having lost its entire seven-man crew.

Then the stories got closer to home: A storm five years ago, when two days of 80 m.p.h. gales halted all departures from the islands, and the “big blow” of 1990, when the Scillonian III, the 1,000-ton, 600-passenger ferry that is the island’s commercial lifeline to the mainland, had to anchor off Land’s End for three days riding out the storm, with a full complement of seasick holiday-goers aboard.

By now, mercifully, it was obvious something was happening out there in the fog. Some blinking lights were visible, and people were coming into view, returning from the quay. The gig race was over.

Andreja, an effervescent Dubliner who is a musician with that city’s National Symphony Orchestra, had joined one of the spectator boats that accompany the gigs in the race, each boatload selecting a favorite to root for. Her gig, the 160-year-old Bonnet, rowed in the winner, “and we were pretty noisy, screaming away out there in the fog,” she said later.

When I arranged my visit to the Scillies months before, I’d wondered if five days wasn’t too long to be spending on a little set of islands well out of the mainstream of activity. Now, as I packed my bags in the early morning darkness and prepared to leave, I thought of a dozen things I hadn’t had time to do--or things I wanted to do again.

I’d spent a day on St. Martin’s, where tons of daffodils are grown for export in the mild winter months and fulmars and kittiwakes nest in cliffs topped by the Daymark, a red-and-white, torpedo-shaped tower that has stood there majestically since 1687 as a daytime navigation marker. But I hadn’t made it to St. Agnes, or Bryher or Samson.

I’d gone back to Tresco to visit the Abbey Gardens. And with Andreja and Petra, I’d taken a final hike through the moors and across the promontories of St. Mary’s, and by now Petra, who also was leaving the next day, was unconsciously shifting back into a London mode, measuring time by the second again and urging us on, as if to meet a schedule.

Tony, the hotel’s headwaiter, had opened the dining room early to be sure I got a decent breakfast before leaving, and he saw me and my luggage to the stop for the heliport shuttle bus a block away. “Yes, people either like it or they don’t,” he’d observed philosophically to my declaration of full satisfaction with the Scillies.

In a sparkling sky, the helicopter brought us back across the pale blue sea to Land’s End and the fields of Cornwall and then Penzance. As it landed, I watched the waiting ground crew inexplicably putting on rain parkas and then as we stepped out onto the mainland once more, a suddenly dark sky erupted with a lashing downpour. As we dashed toward the terminal, the sun broke through and a beauteous rainbow formed, dropping down to the west.

If I were a romantic, I would have said that the end of it seemed to drop into the sea right in the midst of the isles I’d just left.

GUIDEBOOK: The Scillies: Beyond Land’s End

Getting there: From London’s Paddington Station, 10 express trains a day make the five-hour trip to Penzance (about $60 one way); an overnight sleeper (about $120 one way) leaves at midnight and arrives at 8 a.m. From Penzance by sea, the Scillonian III (telephone 011-44-736-62009) makes one trip each way on weekdays, two on Saturday (none Sundays); one-way fare for the three-hour trip is about $45. British International Helicopters’ 32-passenger aircraft make seven 20-minute flights on weekdays during summer, additional flights on Saturday (none Sundays); one-way fare is about $60, and there is a special $90 round-trip fare for travel during specified times (tel. 011-44-736-63871). Reservations are essential in summer, and flights occasionally are delayed or canceled because of bad weather. (For the return trip, I made my train reservation for a few hours after the helicopter flight to allow for possible weather delay.)

When to go: June through August is the best season for weather, and also the busiest. Spring and fall are said to be pleasant, but chillier, and storms are more likely.

Where to stay: There are 10 hotels in the Scillies. Most rates include mandatory half-board--full English breakfast plus dinner-although some accept guests for bed and breakfast at lower rates. Three hotels highly recommended by recent visitors are Star Castle (tel. 011-44-720-22317, fax 011-44-720-22343) atop Garrison Hill overlooking Hugh Town on St. Mary’s (with tennis courts and heated swimming pool); Tregarthen’s (tel. 011-44-720-22540, fax 011-44-720-42089), halfway up the same hill and close to the harbor, with splendid views from public rooms, and Atlantic (tel. 011-44-720-22417, fax 011-44-720-423009) on the waterfront in Hugh Town. Half-board rates at all are about $75 to $105 per person. There are about 70 smaller guest houses, offering varying meal arrangements. “Self-catering” accommodations--apartments or rooms rented by the week, with no meals--are booked up the earliest. The Scilly Tourist Information Center, listed below, publishes monthly computer printouts, beginning in the winter, showing what dates rooms are available at each of the islands’ tourist accommodations.

Where to eat: The hotels’ dining rooms all seem to serve good food, and Tregarthen’s, one of several open to non-guests, provided far more in its tasty four-course meals than I could do justice to. There are a number of restaurants that passed my sniff test and, on menus posted outside, had tempting daily specials, most of them based on local fish and produce. Some examples I jotted down: shark steak and Stilton; leek and Stilton soup; baked gray mullet with mussels; grilled brill with lime butter; cockles and (yes) mussels; fresh John Dory with parsnips; grilled plaice. There are also tea gardens that serve sinful pastries, with homemade jams and clotted cream. One of the best restaurants for scenery and sweets is Juliet’s Garden, a short walk out of Hugh Town.

For more information: The British Tourist Authority, 551 Fifth Ave., New York, N.Y. 10176; tel. (800) GO2-BRIT (462-2748), can provide basic information about the Scillies. Then contact the Tourist Information Center, St. Mary’s, Isles of Scilly TR21 0JL, England (tel. 011-44-720-22536) for hotel and transportation specifics. I ordered the useful “Standard Guidebook to the Isles of Scilly” from them for $4; it describes each of the islands, and their roads and trails and gives information about the plant and animal life.