Ahead of the game: Patient, obsessive, able to trail a fox for 76 hours...welcome to the life of the modern gamekeeper

Tomorrow, the Glorious Twelfth, signals the start of the hunting season – but time on the glen is a year-round occupation for gamekeeper Mark Brown, who gave photographer Will Clarkson an insight into a life of constant vigilance. Warning: graphic content

Mark Brown had never handled a video-game machine before and when he got a PlayStation for Christmas, it drove him crazy. He was so furious at being humiliated by "that bundle of wires and plastic" that he did nothing for the next three days except play it – not even sleeping – until he had completed the game.

This obsessive temperament serves him well in the vast glen in the west of Scotland, where his day job is gamekeeper, keeping the hills safe for the thousands of pheasants reared then shot here every autumn. It is a role he combines with fox-controller, deer-stalker and, deep into the night, working as a highly skilled taxidermist, immortalising many of the stags, hinds, foxes, stoats and buzzards brought down in these hills.

The pay is not great and the hours are insane, but perhaps the worst of the gamekeeper's lot is the public perception, as game-hunting has transformed, during the past half-century, from the dying art of a lampooned and fading aristocracy to the favoured bloody amusement of bankers with bonuses to burn.

In the process, Brown and his colleagues have begun to face the sort of hatred formerly reserved for terriermen at fox hunts, the plebeian hangers-on whose little dogs went down the fox hole to finish off the prey. They are class traitors, that is the implication, and the handsome old tweeds Brown wears to go deer-stalking only seem to bear out the slur.

Tomorrow is the Glorious Twelfth, when the grouse season gets under way, and at the k same time millions of young pheasants are being reared across the British countryside in readiness for the start of pheasant-shooting in October. Cue a reprise of the anti-shooting rhetoric, which depicts the soaring popularity of pheasant-shooting as an index of inequality.

Keeping deer numbers in Scotland under control is essential to preserve woodland and natural habitats. Without these habitats, many Scottish species would be under much greater threat than they already are (Will Clarkson)

The growth of the sport, the polemicist George Monbiot wrote last year, "has been accompanied by a rapid consolidation of land ownership… one of the fastest consolidations of ownership since the Highland clearances… The government wants the resurgent aristocracy to be hampered by as few concessions to the rest of society as possible."

Mark Brown has absolutely no interest in engaging with these arguments, but we might point out on his behalf that, while agriculture has become less and less of a going business proposition in this country, hunting has taken up a great deal of the slack, offering employment to those who would otherwise drift to the cities.

The Game & Wildlife Conservation Trust (GWCT) also claims the sport plays a vital role in husbanding the land: landowners have a powerful vested interest in preserving their woodlands in a state in which the pheasants can thrive, until blasted from the skies.

This is a more controversial claim: while it is illegal to kill birds of prey which are a threat to young pheasants, such as buzzards, their numbers have certainly not multiplied in these areas, and pheasant landowners have every reason not to encourage them.

There are natural highways in nature, and rivers are major ones. This is where Brown will trap the weasels that he wants to keep away from his pheasants. Here he is setting a trap just off the path inside the riverbank. These are small traps, designed to target specific species. Too large, and you risk killing a protected pine marten. Legislation on trapping is constantly evolving to be more humane (Will Clarkson)

But whatever one's view of the politics of the sport – and in reality it is far more an ideological than an ecological debate – there is no doubt that the presence of a man like Mark Brown in the countryside helps to keep it in good shape. As the photographer Will Clarkson emphasises, "Scotland is a mosaic of cultural landscapes, not wilderness landscapes.

The distinction is essential: we have heavily influenced just about every landscape in the country, either directly or indirectly. We have changed too much of the ecosystem to simply walk away, and our continuing interference is essential to maintain some form of balance.

With too many foxes, a great number of ground-nesting birds will suffer; too many hen-harriers will cap red-grouse numbers, for better or worse; too many deer will damage forest coverage, and so on. Balance is key."

Brown's back-room is packed with his work and the odd uncollected piece for a client. His obsessive attention to detail seen in his taxidermy work extends into the glen: he will spend a great deal of time watching animals, just to work out how they look when alive and relaxed, so he can better replicate them at home (Will Clarkson)

Keeping that balance requires all the skill in Brown's possession. Foxes are quite as cunning as their ancient reputation claims, as British city-dwellers are beginning to discover for themselves, and keeping their numbers in check – no more than that – takes all of Brown's skill, and a great deal of his time.

It's a battle of wits and patience: the longest he has ever staked out a fox, waiting for it to return to its den is 50 hours. "About 76 hours straight is the longest I've ever followed a fox's trail without sleeping," he adds, "and I don't fancy doing that again."

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