They are knocking down more terraces in Middlesbrough. As we walked through the condemned area the silence was eerie. All those years of humanity, with its laughter, tears, anger, commotion and joy, had been choked off behind tall metal railings. A loud rumbling began. A crane on tracks grumbled into view. A wrecking ball dangled from the crane’s elevated arm. The ball swung against a house. Even from where we stood, I not only saw the house totter but also the sparrows fleeing the battered roof. They flew over us and shot into a row of bushes. The line of bushes, 20 yards long and gracing an area of more modern housing, was loud with cheeping. At least two dozen sparrows perched on the hidden branches; they seemed even louder than the demolition crane and the usual crash of urban t