Terence

The Big Brother Bird/Fat Bird (a.k.a. Big Red Bird) is the seventh bird used in Angry Birds. It's described as the larger counterpart to the Red Bird, having much more strength. When launched, it will result in Big Brother Bird grunting. However, he's more powerful than his little brother, the Red Bird.

Big Brother Bird is first introduced in the episode The Big Setup and are used for the majority of the episode, starting from Theme 9-1. It is the only bird that can easily smash through about one block of stone, and it doesn't need a special ability to smash through all types of obstacles. Instead, it uses its weight to crush through objects. However, his strength varies depending on what block(s) he's used on, as a large square block will almost always stop Big Brother Bird in his tracks.

The Big Brother Bird is the 3rd largest bird of all. The largest bird is the Mighty Eagle. The Orange Bird is bigger than the Big Brother Bird only when inflated, but is still smaller than the Mighty Eagle.

Trivia

 * The Big Brother Bird, Black Bird, (except in Angry Birds Rio) and the Orange Bird are the only birds without a Corpse Sprite.
 * Red Bird and Big Brother Bird are the only related birds.
 * In the Christmas Comic, it was revealed that his name was Terence when Red Bird had a conversation with him about preparing for Christmas. Therefore, making him the only bird who has a known name. He also sometimes has the personality of a dog in these comics.
 * The Mighty Eagle was most likely feared by the birds and pigs, while Big Brother Bird is most likely feared only by the pigs. (As evidenced by various pig reactions throughout the comics and animations.)
 * The Big Brother Bird appeared that he broke through something in a cutscene of The Big Setup.