“Quick,” said the guide the moment we stepped into the RSPB visitors’ centre at Saltholme near Middlesbrough. “You must see this.” Clearly excited, he marched us to the ground-floor viewing area, which overlooks a phalanx of bird feeders. A fox cub had infiltrated the protective cage round a ground tray and was helping herself to the seeds. Cartoon cute, ears and snout bristling with intelligence, the cub continued to feed. “I’ve waited all my life to see something like this,” someone said from the group of enthusiastic onlookers. “I never thought I’d get this close.” Using all their famed ingenuity to bypass the many obstacles placed by wardens, the Saltholme fox cubs have been using the feeders for some time. Half an hour