This article lists living orders and families of birds. The links below should then lead to family accounts and hence to individual species.
The passerines (perching birds) alone account for well over 5,000 species. In total there are about 10,000 species of birds described worldwide, though one estimate of the real number places it at almost twice that.
Taxonomy is very fluid in the age of DNA analysis, so comments are made where appropriate, and all numbers are approximate. In particular see Sibley-Ahlquist taxonomy for a very different classification.
Phylogeny
Cladogram of modern bird relationships based on Jarvis, E.D. et al. (2014) with some clade names after Yuri, T. et al. (2013).
Subclass Palaeognathae
The Palaeognathae or "old jaws" is one of the two superorders recognized within the taxonomic class Aves and consist of the ratites and tinamous. The ratites are mostly large and long-legged, flightless birds, lacking a keeled sternum. Traditionally, all the ratites were place in the order Struthioniformes. However, recent genetic analysis has found that the group is not monophyletic, as it is paraphyletic with respect to the tinamous, so the ostriches are classified as the only members of the order Struthioniformes and other rattites placed in other orders.
Order Struthioniformes
Africa; 2 species
Family Struthionidae: ostrich
Infraclass Notopalaeognathae
Order Rheiformes
South America; 2 species
Family †Opisthodactylidae
Family Rheidae: rheas
Order Casuariiformes
Australasia; 4 species
Family Casuariidae: cassowaries and emu
Order Apterygiformes
Australasia; 5 species
Family Apterygidae: kiwis
Order †Aepyornithiformes
Madagascar
Family Aepyornithidae: elephant birds
Order †Dinornithiformes
New Zealand
Family Megalapteryidae: upland moas
Family Dinornithidae: great moas
Family Emeidae: lesser moas
Order Tinamiformes
South America; 45 species
Family Tinamidae: tinamous
Subclass Neognathae
Nearly all living birds belong to the subclass Neognathae or "new jaws". With their keeled sternum (breastbone), unlike the ratites, they are known as carinatae.
Infraclass Galloanserae
Order Galliformes
Worldwide; 250 species
Family †Sylviornithidae
Suborder Megapodii
Family Megapodidae: megapodes
Suborder Craci
Family Cracidae: chachalacas, curassows, and guans
Suborder Phasiani
Superfamily Numidioidea
Family Numididae: guineafowl
Superfamily Phasianoidea: pheasants and allies
Family Odontophoridae: New World quail
Family Phasianidae: pheasants and relatives
Order †Gastornithiformes
Family Gastornithidae (see Gastornis) Family Dromornithidae: mihirungs