Both birds should be the same height unless the problem is you are shooting too slow and by the time you shoot the second bird it is dropping and hard to hit!! Please advise if it is a machine problem or shooter error, if it is a machine problem, what type of machine is it? If it's a shooting problem with the second bird....speed up your first shot until you start missing as many first birds as you are second birds....then, with practice your scores should increase!!