Let's start off with a single Flappy Bird in a testing environment similiar to the game as shown. For a general environment like ours we need to figure out ways to escape the changing environment to survive (Score more).
The simplest approach to arriving to such a solution is whenever the bird gets closest to the pipes, it changes direction to opposite direction. For our case when Bird reaches near to a pipe, the bird inverses it's direction and vice-versa.
The closest distance to pipes will be the limiting value equal to (Lift Force - Gravity Force) in Y - direction and constant velocity in X - direction.
Lift Constant = 10 (Upwards)
Gravity constant = 5 (Downwards)
X - Direction Velocity = 2 (Rightwards)