The Songbird is Elizabeth's guardian and one of the primary antagonists in BioShock Infinite. For the majority of the game, Songbird chases after Booker DeWitt and Elizabeth, trying to reclaim her.
The Songbird was created by Fink Industries solely to make sure that Elizabeth would stay locked on Monument Tower. Due to her imprisonment for nearly 15 years, Songbird and Elizabeth formed a bond together. Infuriated when Elizabeth made her escape with Booker DeWitt, Songbird will destroy anything and everyone in its path to bring her back into custody.