A gundog?s hearing powers and sense of smell are a lot keener than ours and despite what some people might say, their eyesight is better than we think.
Because of this it wouldn?t surprise me in the slightest to discover that dogs can hear shot striking a bird overhead, maybe even pick up an air scent of blood from a pricked bird if the atmospheric conditions are suitable.
I do a lot of picking up with a team of dogs behind the line of Guns and often one of them will take a keen look at a bird that has been shot at, then watch as it towers several hundred yards farther on.
I can only surmise that it?s the way the bird has been struck because when you are several hundred yards behind the gun line there?s no way a dog can possibly hear the shot strike.
One of the best judges of pricked birds I ever owned was actually partially deaf at a young age so I would say a dog?s ability to tell the difference between a hit or a miss involves far more than us mere mortals will ever know.