Sanity Break: Cats and Parrots

The title of this video is Funny Parrots  Annoying Cats. The mystery here is why the cats allow the parrots to annoy them. Somehow these birds know that these cats won’t really hurt them, even if they peck at the tail or steal the cat’s food. I know parrots are awfully smart, but how did they ever figure out how far you can push a cat and get away with it?