I think that I might have cracked it with the sunflower heart feeder hanging on the silver birch tree. I have lengthened the string from which it hangs so that he can't possibly reach the hole in the feeder where the seeds come out even if he tries to hang from his tail like he usually does. However, I think the naughty pigeons have dropped seed out of the feeder which is probably what he's eating. You just can't win!
