Shamus,
Cheney was tracking a quail, left to right. The other guy went out for a bird and was not where he was supposed to be. Its not like shooting targets that stand still. That quail was BOOKIN, heading out & away. Cheney would have been swinging hard to get lined up on it.
When your swinging fast on a quail, pull the trigger and "Then" the orange blob jumps into view, what are you supposed to do? Pellets were probably out the barrel before he saw him.