• True birds.
• Metacarpals fused. Sternum keeled.

Super-order 1. Odontognathae

• New world extinct toothed birds.
• Clavicles not fused. Sternum without keel.
• Wings of vestigial humerus.
  Example :- Extinct Hesperomis, Ichthyomis.

Super-order 4. Neognatbae or Carinatae

• Modern birds. New jaw formed by beak without teeth.
• Sternum keeled. Wings well-developed.

Order 1. Gaviiformes

• Legs short. Toes fully webbed. Patella reduced.
• Tail has 18-20 stiff feathers. Hight swift. Example :- Loons (Gavia).

Order 2. Podicipediformes

• Tail tuft of downy feathers.
• Legs far back on body. Feet lobed.
  Example :- Grebes (Podiceps, Podilymbus).

Order 3. Procellariformes

• Nostrils tubular. Bill covered by horny sheath.
• Plumage compact, oily in texture.
  Example :- Albatrosses, Fulmars, and Petrels. Diomedea, Oceanodroma.

Order 4. Pelecaniformes

• All 4 toes included in footweb.
• Nostrils vestigial or absent.
  Example :- Pelicans, Cormorants, Boobies and Ganuets. Pelecanus, Phalacrocorax, Sula, Moras.

Order 5. Ciconiiformes

•  Long-necked and long-legged wading birds.
• Decorative plumes. Bill abruptly decurved.
  Example :- Herons, Storks, Thies and Harningo. Ardea, Butorides, Egretta ciconia, Phoenicopterus.

Order 6. Anseriformes

• Bill broadened with horny ridges.
• Tongue fleshy, legs short and feet webbed.
  Example :- Ducks, Geese and Swans. Anas, Anser, Cycymas, Aythya, Brent.

Order 7. Falconiformes

• Bill stout, hooked at tip with soft naked skin (cere) at base.
• Feet adapted for grasping with sharp curved claws.
  Example :- Vultures, Kites, Hawks, Falcons and Eagles. Athanis auria, oragyps, Neophoros, Nephoros, Porenopterus, Milvus.

Order 8. Galliformes

• Bill short, feathers with aftershaft.
• Feet usually adapted for scratching and running. Game birds.
  Example :- Grouse, Quail, Pheasants, Turkeys. Gallus, Lagopus, Opisthoconus, Francollinus, Centropus, Pavo cristatus.

Order 9. Gruiformes

• Feathers with aftershaft.
• Weak or strong flight.
  Example :- Games, Rails and Coots. Rallus, Fulica, Gollinula, Porphyrio, Antigone, Anthropoides and Gus canadiensis.

Order 10. Diatrymiformes

• Bill huge. Wings atrophied.
• 4 toes on each feet.
  Example :- Diatryma (extinct).

Order 11. Charadriiformes

• Toes webbed.
• Plumage dense and fum.
  Example :- Shore birds, Waders, gulls. Charadrius vociferous, Capella, Larus, Philohela, Erolia.

Order 12. Columbiformes

• Bill short and slender.
• Tarsus shorter than toes. Crop producing pigeon milk for young ones.
  Example :- Pigeons and Doves. Columba livia, Columbajasciata, Ectopistes, Zenaidura, Crocopus and Streptopelia.

Order 13. Cuculiformes

• Toes 2 infront and 2 behind.
• Feet not adapted for grasping. Tail long. Bill moderate.
  Example :- Cuckoos. Coccyzus, Cuculus, Eudynamis

Order 14. Psittaciformes

• Beaks stout, narrow, sharp-edged and hooked.
• Plumage brilliant green blue, yellow or red.
  Example :- Parrots and Parakeets. Psittacula, Rhynchopsitta, Pachyrhyncha

Order 15. Strigiformes

• Head large and rounded.
• Eyes large and directed forwards. Nocturnal.
  Example :- Owls. Tylo alba, Bubo bubo, Otus, Nyctea, Scandiaca

Order 16. Caprimulgiformes

• Bill small and delicate.
• Legs and feet small. Weak and adapteC for grasping.
  Example :- Goatsuckers, Night jars. Antrostomus, Phalaenoptilus.

Order 17. Apodiformes

• Smallest birds. Legs very short and feet very small.
• Bill small and weak.
  Example :- Humming birds and Swifts. Chaetura, Adagica, Micropus

Order 18. Colliformes

•  Small passer like.
• First and fourth toes reversible. Tail very long.
  Example :- Colies (mouse birds). Colius

Order 19. Trogoniformes

• Bill short and stout with bristles at base.
• Plumage brilliant green.
  Example :- Trogons (Trogon alegans), Pharomacru

Order 20. Coraciiformes

• 3rd and 4th toes fused at base.
• Bill strong.
  Example :- King fishers, Hornbills. Megaceryle, Merops.

Order 21. Piciformes

• Bill stout owl-like.
• Dig insect and larvae out of wood.
  Example :- Woodpeckers, Facamars, Puffbirds, Barbets, Honey guide and Toucans. Upupa epops, Picus.

Order 22. Passeriformes

• Perching birds. Toes 3 in front, 1 behind.
• Includes great majority of all known birds.
  Example :- Crows, Homed Larks, Swallows, Gous, Sparrows, Finches, Starlings, Pipits, Blackbirds, Wood warblers, Tenagers, Wax-wings and Kinglets. Passer domesticus, Molpestes, Kittacinela, Acridotheres, Corvus, Motacilla, Hirundo, Ploceus and Urolovcha.