Just before sunset I noticed this mob at a distance, went to house to get camera with the lens that was mounted rather than take time to switch.

As it turned out after inititially moving away, the chased bird came back and passed over repeatedly. From the time I noticed the mob already in progress, to the last image was 20 minutes. The last images with mob still in progress are just after the sun had set, when it became too dark to continue.

Excuses: Low light resulted in less than optimum camera settings, high ISO, wide open aperture. Low light, and on some the small target size, made focus difficult for auto focus to hit precisely. No easier in MF with the moving target so I left in AF.

It turned out to be a White Tailed Kite chased by Barn Swallows plus Cave Swallows. The Kite went for cover in trees or brush several times but was harrassed out. It also hovered in place several times and descended steeply with wings high and feet and tail downward - more like a parachute than a dive.