I've lately been visiting a Great Horned Owl nest near my house, keeping tabs on the lone owlet (and its mother) as it grows up. On two visits I noticed an Anna's Hummingbird flying about the nest, seemingly checking out the birds. The mother owl couldn't care less about this little rascal buzzing about, but the young owl appeared to be quite interested, and would track the flight of the hummingbird with its eyes and head.

I captured quite a few still photos during one  such encounter, and have strung them together into a short video: