Burst mode and go nuts with it. Small aperture for extensive DoF (f/8?). Shoot with both your eyes open so you'll see where they are everytime. I'll choose AF-C/Al Servo AF over MF because their flight path is unpredictable. Choose only the centre AF point so you'll get more accurate AF. Practice the panning technique. Mind the background; would be easier if you shoot against the sky so as not to confuse your AF. Seasoned birders frequent a particular spot and study the bird's behaviour, flight pattern and habits for days before going for the kill, so maybe have that veteran mentality.
But it's always easier to shoot birds at rest you know.