Two men go duck hunting. They settle down in their hide and start waiting for the ducks. This gets rapidly boring for one of them so he reaches into his backpack and withdraws a bottle of 100 proof scotch. "Want some?" he asks his mate.
"No, I've got to concentrate on hunting ducks."
"Okay..." he says and happily drains the bottle.

They go back to watching for ducks. Again, the man gets bored and gets from his backpack another bottle of scotch. "Want some." he asks again.
"No, thanks" is his reply
"Your loss." he says and happily drains the bottle.

He's pretty sloshed by now, but goes back to help his friend watch for ducks. A minute later, a single duck flies up. "Bang!!!" goes his mates gun. "Damn, missed" his mate says.
The man waves his gun in the general direction of the sky. "Bang!!!" his gun goes.
He kills the duck straight.
"Wow," says his mate, "how did you do that?"
"Well," he replied, "when there's a whole flock, you can hardly miss, can you?"