As the Lord almost said, "If the householder had known at what hour the heron would come, he would not have let him break into his pond." But since this householder does not know when the great fish-eating bird would come, he has to be vigilant and prepare his defences and hope that they are enough!
You may see that around the edges of the pond, there are strings, fishing line, posts, and I hope that they cover all the easy approaches to the water. I know that Mr Heron will not give up and that he will be back; he has been here each morning recently, and I know that he has taken at least one fish out of the pond because he dropped it before he could swallow it. I have been trying to catch him on camera, but he is too quick for me and flies off if sees a glimpse of movement in the house through the windows. If I ever take a photo of the Flying Thief, I will post it on the blog!