When this happens, move close and advance with the dog so that you will be in position to act quickly when the dog locks up on point. When a dog fails to find a bird you hit and saw fall, call the dog to heel and move around to the downwind side of the fall area and send it to retrieve from this new angle. When they move into the wind, dogs tend to sweep the area from side to side, and are more likely to catch the scent of fallen game. When you knock a bird down, do not rush in with the dog to help find it. Instead, stay back a bit and let the dog do its job alone.
Dogs often seem to shut off their noses when the area is all tracked up with human scent.