The bird that can't fly

[ATOB2]

Why is an ostrich specified as a bird, when it can't fly?

[eram]

It isn't whether something can fly that givies it classification as a bird, and the ostrich is not the only kind of bird that doesn't fly. It is classified as a bird because of its inherent characteristics. Birds follow mammals as the second most advanced form of animal life, and they are split into two types: Carinatae which have keeled breast-bones and the power of flight; and Ratitae which have raft-like breast bones and can't fly.

[Dungeman]

birds have feathers - penguins, emus, ostrich, rhea, kiwi, road runner are all birds that have feathers but can't fly. Big Bird (seasame streeet) is not a bird though!