Stars are awarded on how much birds are not used and how much destruction you did. 1 star is awarded for little destruction and not much birds unused. 2 stars is awarded for almost getting big destruction and a few birds unused. 3 stars are awarded for getting a lot of destruction or a lot of birds unused. In every Angry Birds episode but Birdday Party, there is a golden egg hidden for getting three golden stars in all levels of that episode. Sometimes, the amount of birds unused does not count for stars. If there is only 1 bird in a level, the amount of unused birds is not counted. For every bird unused, 10,000 bonus points are awarded.