After a few years of not shooting birds in flight due to my busy schedule, I finally found time to try catching my feathered subjects in the air again a few days ago. My old 5D III and the 400 DO II (plus 1.4x TC III) were retrieved from storage, they still work thankfully. My reflexes are slow as expected, but improved a bit after a few minutes of BIF shooting.
Habitat - Open country or lawns.