Does anyone else's dog hunt?

We walk a set walk each morning and evening round 2 farmers fields, at the end of the walk this is a rabbit warren (thats right huh?) anyway, the minute we get to the entrance of field too Bramble starts stalking, getting low in the long grass and snakes his way up the warren and then he sniffs the air, sits and waits for the rabbits to come. He's not caught one yet but he's given it a good go. - he is most upset for the best part of an hour if the rabbits don't come out.

Anyone else got a hunter?