He's a young bird and he is acting just like a spoilt child. He needs some kills asap to help him to grow up. How many kills has he had? Ive seen birds like this and its frustration, pure and simple.
Your going to have to get some rabbits for him to tackle-make sure he gets a kill everytime you go out ( if poss) and the odd time you dont manage a kill , get him to "kill" your fur lure at the end of each session.
Mixy rabbits will be your best bet until the bird changes his attitude. I know they arent much to look at flightwise, but your bird doesnt think that- it will soon get its confidenc