Flown with many hawks, eagles and vultures, a few condors and fewer osprey.
It seems that when approaching below their altitude you're less likely to spook the bird.
If a hawk or eagle lowers the landing gear, it may be time to leave. From experience with golden and wedge tail eagles, they get quite aggressive near their nest when they have young.
The previously mentioned collision was due to a golden eagle joining the lift we had shared for a while. The hawk lost situational awareness, becoming lunch for the eagle.
Jim