Terror bird (Titanis walleri) with prey, illustration. This extinct, flightless bird lived in North and South America approximately 2-5 million years ago. It stood 2.5 metres tall and weighed roughly 150 kilograms. It belonged to the Phorusrhacidae family of carnivorous flightless birds, commonly referred to as the terror birds. Like other members of its family, Titanis had a huge head with a large curved beak, powerful claws and tiny wings. The prehistoric horse shown as killed prey and in the background are Hipparion sp..