Default [Q] Backing up Android saves?

At long last they've released a full version of Angry Birds on Android, and I'm loving it.

I want to update my Android build to a new one, but don't know how to find my save files for Angry Birds... and now that I've got quite a lot of 3* levels, I don't want to lose them.

Can anyone tell me where the save file is kept so that I can back it up before updating?