Despite centuries of persecution and habitat loss, pine martens have proven themselves to be survivors, and as they expand their range, they’re revealing some surprising secrets. Even a dead pine marten leaves its mark. I won’t forget that first sighting. In front of me lay a beautiful cocoa-coloured animal brought into the public bar of my parent’s hotel in Kilchoan, on the Ardnamurchan Peninsula. It had been caught in a snare and then squeezed into a bloodied game bag. Now it lay on the table revealing an exquisitely furred body so soft to the touch. Its tail was full and…