The popularity of the video game Angry birds, in which feathered friends launch themselves at pigs that have stolen their eggs, may have some people wondering: Do birds get mad in the real world?

Angry birds is a game where players use a slingshot to fire birds at a variety of obstructions to destroy a gang of nasty pigs who have stolen their eggs.

Players of "Angry birds" seek to advance to new levels of the game by sending birds crashing into fortresses built by their nemeses: pigs who have stolen the birds' eggs.