I personally am terrible at the game, but my friend has a knack for it, he is really frustrated that he can't get the other color bird(s), Why?
Your bird is randomly assigned a colour every time you start playing. When you die and start over, you get a new colour.
The colours were not available at launch, but were added in a later update. Your friend may have an older version of the game. Since the game is no longer available for download, that also means it can no longer be updated. If this is the case, your friend is out of luck, I'm afraid.