How to backup your Angry Birds game data

To save your game files, you must have a rooted device and a rooted file manager.

-Use the file manager to go to /data/data/com.rovio.angrybirds/files (the end of the package name may different)
-copy these files: highscores.lua and settings.lua
-After that you can override these files on the target device
-The last step is very important. Make sure these files have read and write permission, but no execute, because it will cause problems.

That's it. :)