The Scottish gamekeeper, or ghillie, was obviously an asset to hunting down an elusive prey. They had unique experience of spotting tiny movements in the landscape. Lord Lovat formed his own regiment of Scouts during the Boer War. They wore elaborate camouflage and were described as 'half wolf and half jackrabbit.' But they really came to prominence during WW1.
Stalkers and 'glassmen' were advertised for in Scottish newspapers. Lovat succeeded in extending the age limit so he could recruit one man, Macpherson of Balavil, who was 62. The youngest was 42. They worked in pairs mainly as observers rather than snipers.
By the end of the war photographic reconnaissance replaced much of their scouting duties but their skills and mentality still exists in the SAS.
In 1918 Country Life reported that the war had a disastrous effect on the marksmanship of hunters which they put down to 'jumpiness' caused by the noise of shells. So the deer of Scotland may have been an unintended beneficiary of WW1.