A northern harrier catches up to a short-earred owl, knocks the small rodent (vole) she was carrying out of her grasp, and catches it's rapidly descending prize before it meets the ground. Harrier has been known to steal a vole froma short- eared owl in mid-air. This is an example of kleptoparasitism, which is when one bird steals another's food.
Once I was lucky enough to watch this irl. An Osprey had caught a fish and was flying off when a bald eagle flew at the osprey and started swooping at it. The osprey dropped the fish and the eagle caught it mid air, then the osprey went on the offensive and got the fish back. It went back and forth like that for a couple minutes before the eagle finally flew off with the fish. They never once dropped the fish, just kept catching it mid air. One of the coolest things to get to see. Wish I had video of it, but this was before phone videos were worth bothering with.
I've never seen this in real life, but I have seen like half a dozen sparrows chasing around a hawk that was stalking one of their nests. It was interesting to see the cooperation. "Not today, Satan!"
Mobbing (the little birds chasing off the big ones) is very interesting to get into. It's one of the few things where animals of different species will work together for the same purpose!