Bird, real name Angel Vallelunga, was the Lieutenant of the South American terrorist, drug dealer, subversive, mass-murderer, and assassin, Bane. Possessing a build of 6'2", 215 lbs, brown eyes, and bald, Bird was one of the prisoners who escaped from Pena Duro, and was thus very loyal to Bane.
Exact details about Angel Vallelunga's life prior to escaping Pena Duro was unknown, as all records of him, if any existed, were lost, although it was rumored that he may have been born in the prison like Bane was. After he was freed from the prison by Bane, Angel took the name of "Bird" and started to commence a lot of terrorist acts and other unspeakable crimes at the behest of Bane. Bird followed Bane's commands to the letter and was willing to lay his life down without hesitation for Bane's cause, which made him a very dangerous criminal for his fanaticism.
Bird arranged with Black Mask to smuggle Bane into Gotham to take a hit on Batman, although Bird alongside the rest of Bane's mercenaries, intended to betray Black Mask and take control of Gotham.
While Bane was trying to hunt down Batman and piecing together his identity, Bird, under the orders of Bane, started to make several shipments of Venom. However, some of Bane's Soldiers ended up meeting opposition at Coventry by several criminals (presumably The Penguin's Gang), which lead to gang fights at Coventry and Amusement Mile over the production of Venom. However, despite the opposition, Bird and the other gang members nonetheless managed to retrieve the chemicals necessary for Venom production. Batman learned of their actions from a police scanner report of a gang war over chemical weapons while he infiltrated Bane's HQ, and managed to track them and the chemicals down to My Alibi based on a card near a birdcage. Bird also took control of the club, and forced their owners to flee after he roughed them up. Bird also spent his time waiting for Batman under Bane's orders, due to Bane anticipating that Batman would try to halt his shipment. Batman then defeated Bird and his men, and left them for GCPD to arrest them, although not before Bird revealed that his being arrested wouldn't even slow Bane down, as all the Venom production materials had already been delivered to him.