Q: How can I remove Angry Birds App.?

Hi ...

From your Mac? Use this utility > Download AppCleaner for Mac - Uninstall your apps easily. MacUpdate.com

From an iOS device, press and hold the app until it jiggles, then tap the x then tap Delete. Then press the Home button once or twice to stop the jiggling.

If you are referring to removing the app listed in iTunes / Purchase History, it can't be deleted but it can be hidden >  iTunes Store: Hiding and unhiding purchases