A lovely spring day in Stockton, and the path took me along one of the gracious little canals close to the River Tees. The sun glittered in the willows; a swan watched me from its nest on a raft of bulrushes. Then, from somewhere in the tall reeds on the far bank, the music began. To start with, the musician was just tuning up, and as it gave a few harsh “chuk-chuks”, I thought it was a blackbird.