Tension spreads by insistent alarm calls from songbirds. It was a morning of small drama along the railway line. The cause of the electric atmosphere was a male Sparrowhawk; the hunter weaves from along the Blackthorn in a hedge-hugging flight alternating between powerful rowing wing beats and fast glides. Every few yards he swings from one side of the hedge to the other. Never more than two feet above it, I felt I could see his cold yellow concentrated eye as he sped along. In fact the hunting pass is over in seconds and the finches had all successfully dived for cover. The panic continues like a corridor ahead of him, whilst in his wake wildlife visibly relaxes and returns to normality.