The Common Kingfisher - Alcedo atthis, is a small kingfisher with seven subspecies recognized within its wide distribution across Eurasia and North Africa. Photo by J van noorwyk. Humph - ain't nuthin' common about THIS feller!
I've seen small birds drive away an owl before, and I think that's what is happening here between a songbird & a Barn Owl. It's astonishing to witness the bravery of small creatures protecting their young and/or their territory.