Birds belong to the kingdom Animalia and the phylum Chordata, which includes animals that have backbones. All birds belong to the class Aves. The order and family differ according to the characteristics of the bird.
The class Aves consists of 23 orders of birds. According to Birds.com, the birds within a particular order share very similar characteristics. More than 50 percent of the members of this class belong to the order Passeriformes. The Aves class contains 142 families, most of which have a name ending in "-dae." Families are further divided into Genus, which are made up of individual species.