Classification of birds

Subclass  ARCHAEORNITHES(Ancient birds)

Order Archaeopterygiformes, Archaeopteryx;Archaeornis. Extinct.

Fossil birds as connecting link between reptiles & birds. Skull rounded like birds; feathers on wings and tail; pelvis and fore and hind limb bones bird-like. Tail long, without pygostyle; bones not pneumatic; thecodont teeth; amphicoelous vertebrae; ribs without uncinate process; tibia and fibula separate; all digits with claws.

 Subclass  NEORNITHES (True birds)

Superorder ODONTOGNATHAE (Toothed birds)

1. Order Hesperornithiformes,  ex. Hesperornis. Extinct.

Duck like, flightless swimming birds with webbed toes and thecodont teeth in jaws; keel and furcula absent; skull bones fused; heterocoelous vertebrae; wings reduced, incapable of flight; found in cretaceous period; body 90 cm long.

2. Order Ichthyornithiformes, ex. Ichthyornis; Apatornis. Extinct.

Gull-like flying birds with few teeth and fish-catching beak; keel and furcula present; vertebrae amphicoelous; carpometacarpus formed in fore limb; body 20 cm long.


1. Order Struthioniformes, African ostrich, Struthio camelus.

Head and neck without feathers; feet with two toes; height up to ten feet and weight up to 150 kg; male incubates eggs.

2. Order Rheiformes, South American ostrich, Rhea americana; Pteronemia pennata.

Head and neck feathered; feet with 3 toes, webbed at base; smaller than African ostrich; eggs lemon yellow, incubated by male.

3. Order Casuariformes, Emu (Dromaeus novehollandae), Cassowary (Casuarius casuarius), found in Australia and New Guinea. 4 species.

Brownish colour; 180 cm tall; aftershaft on feathers; monogamous; cassowaries are brightly colored with horny helmet on the head.

4. Order Apterygiformes, Kiwi (Apteryx australis; A. hoasti; A. oweni).  New Zealand.

Feathers hair-like; wings reduced; tail absent; long beak with nostrils at the tip; acute sense of smell; nocturnal and burrowing birds; lay one egg at a time in burrows.

5. Order Tinamiformes, Tinamous (Eudromea elegans; Crypturellus variegatus); found in South America, south of Mexico; 50 species.

Partridge-like birds, cryptically coloured; not tail; can fly short distances; keel present; palate paleognathous; male incubates eggs which are laid in a nest on ground.

6. Order Dinornithiformes, Moa (Dinornis). Extinct in 13th century in New Zealand.

Twelve feet tall; stout birds with long neck and legs; wings rugimentary; 3 clawed digits on feet.

7. Order Aepyornithiformes, Elephant birds (Aepyornis; Mullerornis). Extinct.

Lived in Madagascar nearly 2000 years ago; height 7-10 feet; body heavily built; legs long and stout with 4 toes; wings rudimentary; eggs 30 cm long.

8. Order Diatrymiformes, Diatryma. Extinct in USA, France, Britain.

Seven feet tall birds with massive head and sharp tearing beak; hallux small; pelvis large; preyed upon small mammals that they ran down.


1. Order Sphenisciformes, Penguins (Spheniscus; Aptenodytes; Eudyptes), 15 species.

Found in southern hemisphere and Antarctica; body streamlined; feather compact, scale-like; fatty insulating layer under the skin; air sacs absent; wings modified, paddle-like for swimming; toes webbed for swimming; beak fish-eating; one egg laid at a time which is incubated on the feet; gregarious.


1.Order Gaviiformes, Divers and loons. Aquatic birds that catch fish and crustaceans by diving; toes webbed; legs short and set far back; migratory. There are two species, Gavia arctica and G. stellata recorded in India.

2. Order Podicipitiformes, Grebes (Podiceps, Podilymbus). 17 species. Aquatic birds with rudimentary tail; bill compressed, pointed; front toes wsdith broad lateral vane-like lobes; nails broad and flattened; feed on fish and crustaceans. Migratory.

3. Order Procellariformes, Albatross (Diomedea), Shearwater (Puffinus). 81 species. Ocean birds with a wing span up to 11 feet; beak long, hooked at tip; wings narrow, long and pointed; feet webbed with strong hind claw; tail short and rounded; hallux reduced or absent; soaring and migratory birds.

4. Order Pelecaniformes, Pelicans, cormorants, frigate birds. 50 species. Large birds with short legs and large webbed toes; upper mandible flattened and hooked at tip; lower mandible has a pouch of loose skin; tail short; food mainly fish.

5. Order Ciconiiformes, Herons, Egrets, Storks, Flamingos. 117 species. Long legs and long slender, flexible neck; bill long straight, sharp and dagger-like; middle and outer toes webbed at base; many migratory.

6. Order Anseriformes, Ducks, Swans, Geese, Teels, Pochards. 149 species. Large conspicuous water birds; bill broad, flat with comb-like margin for straining food particles; wings usually narrow and pointed; tail short; feet webbed; tongue thick and fleshy; migratory.

7. Order Falconiformes, Vultures, Kite, Eagle, Buzzard, Hawk, Falcons. 274 species. Birds of prey; beak short, upper mandible longer and hooked at tip for tearing flesh; feet strong and powerful, with hooked claws; hallus strong; predators or scavengers.

8. Order Galliformes,  Game birds, Megapods, Patridge, Quail, Turkey, Hoatzins, Guinea Fowl, Fowls, Peacocks, Pheasants. 240 species. Terrestrial; legs stout and unfeathered; hind tarsus with a spur in male; claws short, strong and blunt; beak short and stout; legs adapted for running.

9. Order Gruiformes, Crane, Rail, Bustard. 185 species. Small to large ground birds or shore birds; hallux absent; keel is reduced, have weak power of fight; slight web on toes; feed on fish, reptiles and mollusks.

10. Order Charadriiformes,  Plovers, Lapwings, Sandpipers, Pranticole, Gulls, Terns. 293 species. Waders and good fliers; beak variously modified; hallux small or absent; anterior toes webbed; terns have forked tail and short legs; feed on fish.

11. Order Columbiformes,  Pigeons, Doves, Sandgrouse, Dodo. 301 species. Grain or fruit-eating birds; slender beak; legs for perching; eggs pure white; youngs are fed on milky food produced in crop; base of beak covered with a soft swollen membrance in which lie the nostrils.

12. Order Psittaciformes, Parrots, Macaws, Cocatoo, Parakeet. 317 species. Fruit eating birds; bills stout and strongly hooked; upper mandible movable; tongue thick and fleshy; feet zygodactylous; tail pointed.

13. Order Cuculiformes, Cuckoo, Koel, Brainfever bird, Crow-pheasant. 143 species. Feet zygodactylous; young do not grow down feathers; brood parasitic, lay their eggs in the nest of other birds; wings long and pointed; migratory;

14. Order Strigiformes,  Owls (Bubo, Strix, Nyctea, Tyto). 132 species. Nocturnal birds of prey hunting small mammals and reptiles; eyes large, directed forward; upper eyelid large; beak short and hooked, sharp; ear opening large; neck highly flexible; fight soundless.

15. Order Caprimulgiformes, Nightjars, Oil birds, Frogmouths. 92 species. Bill short, flexible with enormous gape; wings long; bristles around nostrils; nocturnal birds, feeding on insects on wing; eggs are laid on ground in a bush.

16. Order Apodiformes (=Micropodiformes), Swifts, Hummigbirds. 388 species. Gregarious, insectivorous birds, adapted for rapid flight; wings long and narrow; tail short and deeply forked; gape of mouth very large; beak short and hooked; feet with 4 toes, all directed forward; legs weak; capable of flying backward.

17. Order Coliiformes,  Mouse birds of South Africa. Short legs with sharp claws for climbing on trees. Crest on head. Feathers hair-like. Gregarious. 6 species.

18. Order Trogoniformes, Trogons of Asia and Africa. Zygodactylous. Insectivorous, Solitary. Base of beak hairy. 35 species. Bill short, strong and wide; base of nostrils covered with bristles; tail long.

19. Order Coraciiformes, Kingfishes, Bee-eaters, Rollers, Hoopoe, Hornbill. 192 species. Three front toes are joined at base; beak long heavy and sharply pointed; nest is built in tree hole; highly variable species.

20. Order Piciformes, Woodpeckers, Honey guide, Toucans. 377 species. Insectivorous.birds, adapted for climbing on tree trunks; feet zygodactylous; beak strong adapted for wood cutting; tongue very long, armed with spines at tip; tail feathers strong to support the body; eggs are laid in tree hole.

 21. Order Passeriformes, Perching birds. Pitta, Flycatchers, Lyre-birds, Skylarks, Swallows, Wagtails, Shrikes, Bulbul, Wren, Babblers, Warblers, Tailor-birds, Nightingale, Tit, Nuthatch, Sunbirds, Tanager, Starlings, Grackle, Oriole, Drongo, Magpie, Jay. 5,110 species. More than half of total number of bird species are included in this order. Feet adapted for perching; front toes are free and hallux long and movable; highly variable species, adapted for various habitats.