Sorry I missed this...
I was going to check the status of the Red-tail nest, when the Red-tail alarm calls drew my attention. The owl was very close to the nest on the ground and the Red-tail was diving on it. The owl looked as it had already been stunned, since it wasn't trying to fly away, but "ducked" everytime the red-tail dove. Finally, the Red-tail actually hit and bound to the owl and they both tumbled in the leaf-litter behind a tree. I couldn't see the tussle behind the tree, but they separated almost instantly with the owl going one way and the Red-tail back up toward the nest.
The owl was probably stunned and probably had a few punctures. I did not check then, (Red-tail was stressed enough) but looked later for lost feathers but found none.
Anyway, both had a story to tell and both were probably alive to tell it for some time.