What is the difference between birds and birds?

Birds and birds are only conceptual differences in size. Bird is the general name of all birds. Birds are just a kind of birds, different from birds that can't fly.

What is a bird? a bird is a general term for flying birds. At first, birds are higher vertebrates evolved from reptiles, and they are the only animals with feathers, so they are also called feathered animals. A bird's feather helps to spread its wings and fly. It also helps to keep the bird warm.

Birds. Birds. The Gao Tang Fu written by Chu Song Yu of the warring States period: "shaped like an animal or a bird." Sui Dao Yuan in the Northern Wei Dynasty? River II: "those who struggle with birds in the sky all fall into deep waves." Xu Chi's Records of Huangshan: "in addition to all kinds of beasts, there are all kinds of birds."

In the animal world, except that birds, insects and bats are really sexual animals. There are also groups of flying fish, squid, flying frog, flying lizard, flying snake, flying orphan, flying mouse and so on. Amphibians, reptiles and mammals can also fly, that is, gliding. But they all have no feathers. So it's not a bird. And flightless kiwi, ostrich, emu, turkey, penguin and so on. It's a bird because it's feathered. It is not a bird to lay eggs without feathers, such as Guiao and ants. In particular, the peculiar platypus, with a rubber-like duck bill, is the only surviving member of the mammal family to reproduce by laying eggs. In taxonomy. They are monopod animals. Although monotremes reproduce in the same way as birds, defecation and spawning are the same excretion channel. But because it has no feathers. So it doesn't belong to birds.