If he's down and flopping after the shot, 99.5% of the time it's a dead bird. The sympathetic nervous system still fires neurotransmitters for about 3 min after the animal is dead.
You can hasten the process in any manner you like. You can either snap his neck, as described by vmartin, or you can just step on his neck.
If you step on his neck, follow these steps:
1) step on bird's neck
2) grab legs, above the spurs
3) jerk the body upwards in one swift motion...
This quickly snaps the spinal column, and gives you much better control. Furthermore, you get the sastisfaction of inspecting his spurs
I typically always finish my birds this way, and have yet to ruin any capes or feathers for mounts. More feathers are ruined by the actual shot than by any post-shot handling. The second way that mounts really get messed up is where the bird lands after the shot. IF they roll down a steep embankment or into water, don't expect a gorgeous mount [&:]