Optional objective: Avoid mid-air collisions.
After speaking with the shaman, you will take control of an eagle and will have to follow a fire bird. During your flight you will see the alternative future of your clan and will learn how to save it.
In order to reach a full synchronization, you should avoid any obstacles on your way. If you hit a tree more than once, you will fail the optional objective. It's not a simple task, though you should make it after a couple times. Try to fly as stable as possible for the most time, don't perform any sharp turns and stay at the upper part of the woods.
The mission will end as you fly to your final destination.