Are birds vertebrates or invertebrates?

Birds have an internal skeleton and a backbone so they are all, regardless of species classified as vertebrates.
As you may already know, vertebrates are animals with backbones and invertebrates are animals without. So, as obvious, birds are considered vertebrates. They are other types of vertebrates. Such as: mammals, amphibians, fishes and reptiles. All birds are vertebrates, meaning that they have a backbone.
Vertebrate means having a backbone. Birds have backbones, so they are vertebrates.