Hee hee! More chattering. Yep, Ziggy does this too... and that kitty in the video probably was looking at a bird. Ziggy does it in his sleep (when he's disturbed) and when he wants to start a fight with another kitty in the house. A play-fight, of course... but he's still young, so he tends to be rough and the other kitties don't necessarily always want to join in. Maybe he feels a need to threaten them.