The cat is killing "everything in sight, he has killed so many bird and it is really getting out of hand" because he's not being fed properly. He's having to forage for his own food. Obviously the cat isn't being taken care of, & as you said the owners "don't give a hoot". They've been given a chance by being talked to & since they still don't give a hoot, then maybe this little guy can go to a family that will give him a hoot & a then some & a much better life. All the nicety steps have been followed, & it's time for action. But I do agree that maybe taking the little guy to a no-kill shelter - or even if you know someone willing to adopt him right out might be best.