All animals belong to a biological kingdom called kingdom Animalia . This kingdom is then divided into over 30 groups, or phyla (plural form of phylum ). Around 75% of all species on Earth are animals. Animals are then broken down into two types: vertebrates and invertebrates. Birds are a type of warm-blooded vertebrate that are adapted to fly. Birds come under the category of reptiles. Birds are in the Phylum Chordata (Animals with a backbone).