I'm saddened to see we've reverted back to solving the problem by steering around birds. There seems to be a great presumption about bird behaviour.
Forget about computer simulations, you need observations and data first.
The birds have been around a long time because they have learned to avoid most predation. Their response is not to just fly along in a flat plane. In fact they can move out of their flight pattern to esacpe a lot faster than the aircraft can.
Most of the available data is recorded bird strike damage to the aircraft and its engines. In an attempt to understand this statitical data some experiments have been made to confirm bird behaviour. I'll leave it to the data collectors and scientists among us to expand on this. But really folks we ought to stop speculating about birds trying to solve a safety of flight problem.