Terratornis

Teratornis were cloned as the body count of creatures grew in the wild, filling it with corpses. They cloned teratornis to deal with the problem, and as an attraction. They flew to other islands, preying on rats that lived there. They flew away from the hijackers when they captured many creatures. Eleven teratorns and two nest fulls were taken to mainland, where everything went wrong. They ended up flying away and breeding like rabbits until the final chapter of apocalypse. The final scene shows teratorns and Argentavis feasting upon the main antagonist.