Terror Birds

Gastornis and Phorusrhacos are called "Terror Bird " because they were good hunters and fast.but the difference of this two bird are Gastornis live in Eocene and Phorusrhacos live in miocene.Their diet is small creature and cubs.Their extinction is because predators hunt its eggs for food and difficult to have offspring.one more thing,the terror birds cannot fly because their wings are to small just like ostriches.