Clyde, being the ever-inventive little mystery he is, has come up with a new mannerism to puzzle his mommy. He has started doing this twitching tail thing, like a tail shimmy, and I can't decide if it's a good twitch or a bad twitch.

He's done it both when he should be happy and when he might be annoyed. I dimly remember someone else asking about a shaking tail somewhere, but I can't remember which category it was in or what the topic title was or what the consensus was on why birdies do this.