Peeved Avians

The hot smartphone game is Angry Birds. Grown ups and kids love it.

In the game, players use a slingshot to launch birds at pigs stationed on or within various structures, with the intent of destroying all the pigs on the playfield. As players advance through the game, new birds appear, some with special abilities that can be activated by the player.

I've tried it. It's fun. But something puzzles me...

The pigs don't exhibit much - if any - aggression.
Maybe the birds need an anger management session?