Why do we get only a couple of good flights in September and then very little for the rest of the season?

There are several possible reasons for this, the most likely of which is shooting too often. A pool can rarely be shot more than once every three weeks without driving the ducks away. It also pays to try to leave the pond before the flight is fully over. In this way, a small lead of birds is able to come in undisturbed at the end of the flight, and maintain continuity till next time.