O.K. Now I see in my mind's eye where you are walking him and having problems I can suggest a stategy to help turn him off the little running away things and on to you.
Some off lead work is going to help a lot.
Some consistent Alpha signals from you will also help to convince him that it is not up to him to choose when and what he hunts, that's your job as pack leader.
Whistle training is going to help him too - a very clear signal that he can't misinterpret and cannot fail to hear.
Once he is used to the whistle and is running after something you use the whistle once, turn, and run as fast as you can the other way!! If you can get in behind a tree or hedge to hide and wait that would be great.
After a couple of times doing this start doing it as soon as you see a potential chase animal. If the dog sees it first, do it as soon as you realise he has spotted something.
Let us know how you get on with this if you decide to try it.