Classification of Birds

There are more than 8,500 species of birds alive today, compared with only about 4,000 species of mammals. Apart from the nocturnal species, most are fairly easy to observe.

The Orders of Birds
Birds (class Aves) are classified into two subclasses, Archeornithes and Neornithes. The Neornithes consist of 4 superorders: Odontognathae, extinct toothed birds; Ichthyornithes, also extinct; Neornithae and Impennes, containing all other birds, generally arranged into 28 orders (including some extinct orders), subdivided into 158 families. The classification is based only on anatomy, behavior and life history.

Order Struthioniformes
The ostrich, the largest living bird, is the only species in this order. It is a flightless bird, found today in the wild only in Africa. Several other groups of birds have also evolved a lightless lifestyle. Together with the ostrich, they are known as ratites. They have strong, stout legs for fast running.

Order Tinamiformes
The tinamous are a group of about 50 species of beatiful birds restricted to South and Central America.

Order Gaviiformes
The divers or loons are a primitive group of 5 species of waterbirds found only in the colder parts of the Northern hemisphere.

Order Procellariiformes
This order consists of oceanic species with long tubular nostrils. They seldom come to shore except to breed, and all have webbed feet. Best known are the large albatrosses.

Order Pelecaniformes
A group of large, fish-eating waterbirds, they are the only birds with all 4 toes webbed. The other families are the gannets, or boobies, which dive vertically into the sea for the fish from the height of 100 feet.

Order Ciconiiformes
This order consists of large, long-legged wading birds. The 60 or so species of herons, egrets, storks and bitterns have dagger-like bills for spearing fish and other prey.

Order Anseriformes
The swans, geese and ducks are included in this order, which contains more than 150 species.

Order Falconiformes
This order comprisess the birds of prey. A large order with almost 300 species, it includes the carrion-eating vultures and condors. All Falconiformes have powerful, sharp, hooked beaks for tearing flesh, and strong feet armed with sharp talons with which they catch their prey.

Order Galliformes
Game birds belong to this order including megapodes, grouse, 180 species of pheasants, and guinea fowl.

Order Gruiformes
These are ground-nesting, ground-feeding birds. Many are poor fliers, although the migratory cranes are a striking exception. Large, long-legged, gray, white and black or brown birds, the 15 species of cranes inhabit Eurasia, North America and Australia. There are about 130 species of rails.

Order Charadriiformes
This order consists of the wader, gulls and their relatives, typically found on or near seacoasts and freshwater. The waders are a huge group of over 200 speceis. They feed on fish, small mammals, birds and their eggs, and also chase gulls, terns and other birds forcing them to disgorge their food. The auks are short-winged diving birds restricted to the northern oceans.

Order Columbiformes
This order consists of pigeons and doves (284 species) They live on seeds, fruits and berries. They are able to drink by a suction action without lifting their heads from the water.

Order Cuculiformes
This order includes the 18 species of brightly colored turacos from the jungles of Africa and the cuckoos (more than 100 species), some of which are parasitic breeders. They lay their eggs in the nests of other birds.

Order Strigiformes
Most of the 131 species of owls are nocturnal birds of prey with large eyes. They are subdivided into 10 species of barn and bay owls and 121 species of typical owls.

Order Caprimulgiformes
This order contains about 95 species of nightjars (sometimes called goatsuckes ) and their relatives. Nocturnal birds related to owls, they have long pointed wings and bills fringed with bristles for trapping flying insects.

Ruby-throated hummingbird female
Ruby-throated hummingbird (female)
Photo by Laura Johnston

Order Apodiformes
All the members of this order are exceptional fliers and tiny feet that are useless for walking. The swifts are the most aerial of all birds, able to fly for days on end even sleeping on the wing. The 85 or so species are found worldwide. They feed on nectar and insects.

Order Coliiformes
This order consists of single family of mousebirds. All 6 species are Afican.

Order Trogoniformes
This order contains the brightly-colored tree-dwelling tropical trogons which have unusualy delicate skin.

Order Coraciformes
This orderThe brightly colored, mainly tropical birds of this order nest in holes in banks or trees. They include 87 species of kingfishers, 8 species of motmots, and 8 species of bee-eaters, 16 species of rollers, and 8 species of wood hoopoes and hoopoes, as well as the 44 species of hornbills.

Order Piciformes
Birds in this order include 208 species of woodpeckers and gint-billed fruit-eating tucans (37 species) of the tropical rainforests of Central America.

Order Passeriformes
This order, the perching birds, is the biggest group of all, containing more than a third of all living families and over half the living species. All have feet adapted to perching on or clinging to branches or other supports. The order includes the "song birds," which have developed the ability to sing to the highest degree. It also contains the swallows, wagtails and pipits, wrens, thrushes, warblers, tits, finches, weavers, and sparrows, starlings and crows.


  1. Mike Janson and Joyce Pope (consultant editors). The Animal World

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