Jay, Jake and Jim

The Blue Birds (aka Cyan Bird, Light Blue Bird, Splitter Bird, or Glass Jaw) are a species of Birds used in the Angry Birds series. First debuting on the Theme 1-10, these birds are the weakest of the eight, but have the unique ability to multiply into three identical copies which fly into the pigs and their buildings.

It can be used in two ways. The first way is to multiply it when the player releases it to hit the targets in one time. The second way is to multiply it right before the bird crashes onto the building, to either break through ice or to push buildings down. Due to their lack of strength, they're mainly designed to destroy glass blocks. However, it's a must to multiply it to provide a triple force for tighter breaking the glass blocks or to push a whole building down. It's not the smartest bird of flock, as shown in the Angry Birds Rio video when it keeps singing and doesn't notice the cages falling until the Yellow Bird nudges it. In Mighty Eagle, Angry Birds Rio and Bing cinematic trailers, the blue bird has white spots.

Trivia

 * The Blue Bird is the only bird who is smaller than the eggs and the other birds.
 * The Blue Bird is the only bird who does not have eyebrows.
 * The Birds have three parts of their tails, while the Blue Birds have two.

in angry birds and the mighty eagle and angry birds rio trailer blue birds   have eyebrow