My daddy can beat up your daddy

Sharp-shinned hawk (Accipiter striatus) Cooper's Hawk (Accipiter cooperii)*

We heard a thump this morning over coffee but found no explanation for it. Shortly afterwards we noticed this guy creeping up to our front doorstep. Very unusual.

Then we saw blood spots on the deck, blood and feathers on the door, and a very frightened robin under the bench, which the hawk was closing in on. We did not interfere, except for my camera clicking away behind the window. The hawk gave up after a few minutes of stalking and flew off, possibly because the robin was successful in merging into the shadows without moving, or possibly because the hawk detected too much human scent around our doorway for comfort.

The robin was able to fly away shortly after that.
We noticed the bands on the legs. One says 5K, and the other is not quite legible.

*Update: The person who banded it says it's a Cooper's Hawk, male, yearling. He provided a photo from the banding. This hawk is 2nd from right in his photo.