Jay, Jake and Jim

Blue Birds (A.K.A. Glassjaw Birds or  Cluster Birds) are a species of Birds in the Angry Birds series. First debuting in Theme 1-10, these birds are the weakest of the eight, but have the unique ability to multiply into three identical copies to fly into the pigs and their buildings. Like most abilities, it is triggered by clicking the screen with your mouse or finger (depending on the version)

Blue Bird's splitting ability can be exploited in different ways. By splitting just before impact with an obstacle, the three birds' force on impact is concentrated for maximum force. Or the birds can be split early allowing them to spread out and hit more obstacles at once. While a Blue Bird has difficulty with most obstacles, it does have a unique strength against glass: able to penetrate glass walls with surprising ease.

Blue bird is based upon the Red-cheeked Cordon Bleu. It is also classified as very small for size.

Trivia

 * The Blue Bird is the only bird that has no eyebrows, although they have eyebrows in some cinematic trailers.
 * According to the comics and animated shorts, the three blue birds are juveniles, younger than the others. They are cheerful, optimistic, funloving, and are pranksters.
 * In Year of the Dragon Animation, the bird silhouettes watching the play from afar are three Blue Birds
 * Blue Bird was the first bird to meet Orange Bird in the Ham'o'ween introduction video.
 * Its eyelids appear to be different colors in each appearance. In the games, their eyelids are Blue (most easily noticed in Angry Birds Rio), whereas in the Angry Birds Seasons animations (with the exception if Summer Pignic), their eyelids are red.