When screws and bits of metal started appearing in a bird feed container an infrared camera helped solve the mystery.

Steve Mckears, who lives in Severn Beach, near Bristol, said the problem started mid February when he found a screw in among the peanuts he was preparing for the birds.

He said he removed the screw but the next day there was "a load more in there".

After the objects kept returning he enlisted the help of a photographer who installed a motion-operated night vision camera.