The mowers have arrived. Quiet, sightly, non polluting of the atmosphere, cheap to maintain, they have got to their destination just in time. The grass was becoming dangerously long in certain parts of the golf course.

I did say mowers, didn't I? And I meant mowers. But not the kind that have to be transported to each green on the back of a petrol-guzzling tractor. Something far more adventurous, more historic, absolutely in keeping with a Site of Special Scientific Interest, even if they have to be inspected every month or so by officials from Scottish National Heritage.

When I wrote mowers I meant sheep. Black sheep furthermore.

Sheep work for nothing, don't answer back or fail to start on cold mornings. They are environmentally friendly, do not need to be fuelled by petrol or charged with electricity and do not require a roof over their heads at night. On the whole sheep are unlikely to say, as drivers of power-driven mowers are: "Oh bugger this for a game of soldiers, I'm off to see the Manchester United game." In short, they look good. So good in fact they are on the Machrihanish Dunes' logo.

There was something really pleasing about hearing that 25 Black Hebrideans, so named because they are black from top to toe, had been shepherded on to the Machrihanish Dunes course by sheepdogs and then left alone to start munching, joining the White Suffolk sheep that are already there. There may be shock at the thought of sheep on a golf course and I grant you that the idea of furry quadrupeds on, say, Loch Lomond or the West course at Wentworth does sound incongruous.

But know your golf history. Remember the role of sheep in golf. Shepherds holding crooks, tending their sheep, which scraped the soil away to make defences against the wind and rain thus creating the earliest form of bunkers as well as munching away at the fertile, sand-based land that linked the sea to the nearest centre of population.

There were sheep at Minchinhampton in Gloucestershire, at Brecon in south Wales, the old courses in both cases. At Aberdovey in mid-Wales the farmers above the course had the right to bring their cattle down from the hills and graze on the course. The goats at Lahinch in Ireland are described as barometric. Golfers wondering whether it is about to rain are instructed to "see goats." The club website explains: "If goats are grazing on the dunes the weather will remain fine but if they venture towards the side of the clubhouse then prepare for a spot of rain."

Sheep on a golf course conjure up mental images of fences, sometimes charged with low voltage, to keep them off the greens. At Machrihanish the Black Hebrideans, chosen for their sturdiness and hardiness, roam over the 260 acres the property covers and thrive on the grass found among the dunes.

"They move away when golfers are about, though one was hit on the leg on the 9th hole today" Keith Martin, the keeper of the green, said. "But he gave himself a shake and wandered off. Their droppings have to be cleared each morning and sometimes they urinate on the putting surfaces leaving marks the size of a 50p. But on the whole they are no extra trouble.

"It rarely freezes on this coast of Scotland because of the Gulf Stream. Perhaps half a dozen nights a year unlike the east coast where I have known frost to be in the ground to a depth of one foot for two to three weeks. So we will leave the black Hebrideans alone though we might put some extra nutrition out in the height of winter."

The black sheep at Machrihanish Dunes could become as much a part of this ambitious project as the lighthouse is at Turnberry and the wicker baskets atop the flagsticks are at Merion golf club in the US. Just to make them even more unusual, for two months a year the sheep will be given a holiday. They will be removed from the course to allow the rare orchids to bloom in June and July.

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