There are so many layers of "fake - gotcha!" in this that I can't be bothered doing anything but laughing. See the "making of" bird poops in mouth inside.
From Bob and David:
I made this Behind the Scenes video on the shoot of my FIRST! commercial... ...to show a glimpse of how the process works. You'll see that the advertiser can get far too hands-on, and yet somehow the Director, in this case--ME, can pull a daisy out of a turdpile.