Not long after I first became acquainted with the owner of the hovel in the hills, I was obliged to participate in an 'expedition to the whelks'.

To the uninitiated this took some explaining, especially as the long term objective of the said expedition was revealed to be the purchase of a chainsaw.

We set out on our bicycles, a plastic bucket hanging from the handlebars, inside which were a sack and a piece of string, some sandwiches and a flask. Our destination was the seashore and the task ahead was to gather large quantities of `whelks' - enough to fill a very large orange net sack.

Biologically speaking, the whelks of this particular coastline are more correctly identified as the Common Periwinkle, Littorina littorea. They can be found almost anywhere along the seashore, hidden among the rocks and seaweed, below the high watermark. Dark grey or red in colour, they are about the size or a marble; herbivorous, they graze on seaweed and can be seen emerging headfirst from the shell to feed.

It can, I learned, be profitable to gather winkles. Shellfish merchants up and down the west coast buy them by the hundredweight, for which anything between £35.00 and £90.00 can be paid according to their relative abundance or scarcity - the higher price usually prevailing in the months before Christmas when an hour spent on the seashore can be a cold and demoralising one.

They are then shipped off in vast refrigerated lorries to fish markets in London and Paris. Many of the winkles gathered on Coll are destined for Spain, to be cooked and eaten there. One can only speculate as to why they are so popular elsewhere: not many local people will confess to a dietary treat of winkles.

It is hard to imagine how you can fill a bucket, let alone a sack, with those tiny things. The novice winkler can waste time and energy picking the solitary ones, those that sit high and dry on the rocks and are dropped one at a time into the bucket. A veteran however, will scramble undaunted into the rockiest, weediest and slippiest of gullies, where gregarious winkles gather in colonies, ready to be scooped up by the handful. In this way the bucket is filled faster.

That first time we gathered steadily for a couple of hours: three buckets to fill the sack and that long slithery sound as the bucket of winkles is poured into it, the sack then being 'bounced' on the rocks to let the water run away. Our hands scrabbled in the seaweed, turning rocks over and plunging deep into rock pools to bring up handfuls of the small glistening shells. I was very much a novice, but I was learning fast.

The pattern of a daily expedition to the shore was repeated for six days. The pile of bulging orange net sacks - safely stashed on the shore to be covered by the tide every day in order to keep the winkles alive - grew ever larger and, on first closing my eyes, night-time sleep was preceded by images of endless rock pools full of winkles.

On the seventh day we rested. Not, I hasten to add, because of some overwhelming religious conviction, but because the tides were no longer `right'. Winkles are best gathered during the spring tides of the full and new moon, when the receding tide leaves vast areas of the foreshore exposed. Here the hunting grounds arc at their best. With spring tides only occurring for two weeks out of every four, the dedicated winkler finds it possible to have a regular weeks `holiday'.

This is probably a good thing, winkles being like every other living resource: their numbers are finite and they do not replace themselves overnight when removed. For this reason it is also wise to go to different `spots' every time, so lessening the impact on one particular bit of shoreline. A full sized winkle is probably several years old.

In the summer months daylight hours are often long enough to give two `winkling tides' in one day. The prospect of a `double chance' at turning an extra penny frequently caused the alarm clock to be set at an ungodly hour for that first chance at the seashore - but I don't believe we ever actually made it, a bit more sleep being infinitely more attractive.

In days gone by, most island families would supplement their incomes by picking whelks. In the precarious and marginal economy of the islands, any way of earning a little bit of extra cash was welcome and there is no doubt that `whelk money' has carried many an island family through hard times - and bought many a welcome treat as well. Some individuals even gained a certain renown for their expertise and dedication.

In those days, as now, the winter months were the most lucrative - and this is when winkling ceases to the pleasant and diversionary occupation that it can often be in the summer when the silence of the shore is broken only by the murmur of waves breaking onto the nearby rocks and it is possible to hear the steady 'clink,clink' of winkles being dropped into the bucket. In winter, the rock pools are ice-cold; fingers become numb and difficult to coordinate; the sea crashes loudly onto the rocks and the wind howls around your ears. Bundled up in as many waterproof layers as possible, you discover that it is no longer so easy to bend to work. Carrying the full sack on your shoulders away from the shore, the main difficulty is to keep steady on your feet as the wind knocks you of balance. That is when the `winkling pound' becomes a very well earned one, when the fair-weather-winkler is distinguished from the tough old die-hard.

Winkling can, at best, be described as a marginal activity, satisfying some of the hunter-gatherer instincts that have become suppressed after so many years of increasing `civilisation'. It is an activity that I instinctively enjoy - except on the wettest and coldest of days - and an excuse to spend long hours on the shore.

Over the years, friends and family have participated: babies in backpacks; toddlers eager with their small buckets but prone to wading too deep in rock pools; the vegetarian friend who really could not enjoy herself feeling sorry as she did for the winkles as they were scooped out of their watery holes.

But we don't gather winkles quite so much now. Better things, as they say, have come along. The hovel in the hills is more substantial now - and who, after all, will `go to the whelks' when they don't have to?