I can't vouch for the validity of this video, but here's Ajax the Parrot rooting for the Kansas City Chiefs. Really. I want to believe. Ajax says, "Go Chiefs go" over and over as announcer Kevin Harlan calls a game in the background.
The YouTube video description says: "My parrot Ajax cheering for the Kansas City Chiefs. Kansas City's own Kevin Harlan can be heard in the background doing the play by play. Now when he hears Kevin's voice calling any game he starts the cheer." This is pretty awesome.
H/T: Arrowhead Pride.