The annual pilgrimage to catch the barrel-chested salmon of the River Findhorn was, in terms of fish caught, a personal disaster. The whole party only managed two in the week, but the weather was against us. Just when we needed rain in Scotland, it turned into the Gobi Desert. The resident salmon grew black in the fresh water and sulked in the pools; their silver-backed relations, which have an instinct to snatch at a well-presented fly, waited in the estuary.

There was plenty of time to watch the arrival of autumn. The birch trees were blushing yellow and pink, the rowans hung heavy with clusters of ruby-red berries, and, high above, huge skeins of newly arrived geese gabbled their way across soft skies. Walking along the steep banks remained as perilous as ever, the hard granite and unseen slippery deposits both likely to trip you at any moment.

Once, I met a red squirrel, just a few yards in front of me. We stared at each other for several minutes before we went our separate ways. One day, the grey squirrels will arrive and little Nutkin will disappear forever, for, unlike the salmon, he needs more than rain to be persuaded to stay in what has been his home for thousands of years. His fate is like a ticking time bomb unless the greys can be stopped.