I strangely found this game to be awesome, although I normally dislike creepy stuff in general, and harming people or one's self in particular. Call me weird if you want :)
Anyway, let's speak of the real question here : does the bird's eye charm have a function? And is this a bug to be, sometimes, able to complete it by picking two times the same bird?
On a more general topic, you would be a true benefactor of mankind if you could tell me if there is another, hidden ending to unlock, or if I'm just looking for something that does not exist :)