Birds are warm-blooded vertebrates characterized by feathers, toothless beaked jaws, laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight skeleton. Birds occur globally ranging from tiny hummingbirds to huge flightless ostriches.

There are about ten thousand species of birds and categorized into passerines and non-passerrines. More than half of all bird species are passerines (perching” birds). Birds have wings which enable their flight, and these vary depending on their flight types and lifestyles. The only known groups without wings are the extinct moa and elephant birds.

Wings are modified forelimbs, giving birds the ability to fly. In some groups such as the ratites, penguins and some endemic island species, the wings have been modified for swimming or reduced due to the of the need for flight as a mean to evade predators.  

Many social species of birds pass on “cultural” knowledge across generations. Birds are social, communicating with visual signals (courtship displays), calls and songs, and participating in cooperative breeding and hunting, flocking, and mobbing of predators.

Most bird species are socially monogamous, usually for one breeding season at a time, sometimes for years, and rarely for life. Other have polygamous breeding systems that with one male to many females or, rarely, polyandrous with one female with many males. Birds reproduce by laying eggs which are internally fertilised through sexual reproduction. The eggs are laid in a nest and incubated by the parents, followed by an extended period of parental care after hatching which included feeding nestling chicks sometimes even for a few days after leaving the nest and fledging.

Many species of birds are economically important as food for human consumption and raw material in manufacturing, with domesticated and undomesticated birds being important sources of eggs, meat, and feathers. Songbirds, parrots, and other species have also been exploited for the pet trade, while Guano (bird excrement) is harvested as fertiliser. Today, human activity threatens about 1,200 bird species with extinction, though conservation efforts are underway to protect them. Recreational birdwatching is an important part of the ecotourism industry in many parts of the world.

Source: Wikipedia

Bird Families

Family Acanthizidae
(Thornbills and Allies)
Family Accipitridae
(Hawks, Eagles, and Kites)
Family Aegithalidae
(Long-tailed Tits)
Family Aegithinidae
Family Alaudidae
Family Alcedinidae
Family Anatidae
(Ducks, Geese, and Swans)
Family Anhingidae
Family Ardeidae
(Herons, Egrets, and Bitterns)
Family Artamidae
(Woodswallows, Butcherbirds, Currawongs, and Peltops)
Family Bucconidae
Family Bucerotidae
Family Burhinidae
(Thick-knees and Stone-Curlews)
Family Cacatuidae
Family Campephagidae
Family Capitonidae
(New World Barbets)
Family Caprimulgidae
(Nightjars and Nighthawks)
Family Casuariidae
(Cassowaries and Emu)
Family Cathartidae
(New World Vultures)
Family Certhiidae
Family Charadriidae
(Plovers and Lapwings)
Family Chloropseidae
Family Ciconiidae
Family Cinclidae
Family Cisticolidae
(Cisticolas and Allies)
Family Climacteridae
(Australasian Treecreepers
Family Columbidae
(Pigeons and Doves)
Family Coraciidae
Family Corvidae
(Crows, Jays, and Magpies)
Family Cotingidae
Family Cracidae
(Guans, Chachalacas, and Curassows)
Family Cuculidae
Family Dicaeidae
Family Dicruridae
Family Emberizidae
(Old World Buntings)
Family Estrildidae
(Waxbills and Allies)
Family Eurylaimidae
(Typical Broadbills)
Family Falconidae
(Falcons and Caracaras)
Family Fregatidae
Family Fringillidae
(Finches, Euphonias, and Allies)
Family Furnariidae
(Ovenbirds and Woodcreepers)
Family Glareolidae
(Pratincoles and Coursers)
Family Grallariidae
Family Gruidae
Family Haematopodidae
Family Hirundinidae
(Swallows and Martins)
Family Icteridae
(New World Blackbirds and Orioles)
Family Jacanidae
Family Laniidae
Family Laridae
(Gulls, Terns, and Skimmers)
Family Leiothrichidae
(Laughingthrushes and Allies)
Family Locustellidae
(Grassbirds and Allies)
Family Maluridae
(Fairywrens and Allies)
Family Megalaimidae
(Asian Barbets)
Family Megapodiidae
Family Meliphagidae
Family Meropidae
Family Monarchidae
(Monarch Flycatchers)
Family Motacillidae
(Wagtails and Pipits)
Family Muscicapidae
(Old World Flycatchers and Chats)
Family Nectariniidae
(Sunbirds and Spiderhunters)
Family Nyctibiidae
Family Odontophoridae
(New World Quails)
Family Oriolidae
(Old World Orioles)
Family Orthonychidae
Family Otididae
Family Pachycephalidae
(Whistlers and Allies)
Family Pandionidae
Family Paradisaeidae
Family Paradoxornithidae
Family Pardalotidae
Family Paridae
(Tits, Chickadees, and Titmice)
Family Parulidae
(New World Warblers)
Family Passerellidae
(New World Sparrows)
Family Passeridae
(Old World Sparrows)
Family Pelecanidae
Family Pellorneidae
(Ground Babblers and Allies)
Family Petroicidae
(Australasian Robins)
Family Phaethontidae
Family Phalacrocoracidae
(Cormorants and Shags)
Family Phasianidae
(Pheasants, Grouse, and Allies)
Family Phylloscopidae
(Leaf Warblers)
Family Picidae
Family Pipridae
Family Pittidae
Family Ploceidae
(Weavers and Allies)
Family Podargidae
Family Podicipedidae
Family Pomatostomidae (Pseudo-Babblers)
Family Prunellidae
Family Psittacidae
(New World and African Parrots)
Family Psittaculidae
(Old World Parrots)
Family Psophodidae
(Whipbirds and Wedgebills)
Family Ptilonorhynchidae
Family Pycnonotidae
Family Rallidae
(Rails, Gallinules, and Coots)
Family Ramphastidae
Family Recurvirostridae
(Stilts and Avocets)
Family Regulidae
Family Rhipiduridae
Family Rostratulidae
Family Scolopacidae
(Sandpipers and Allies)
Family Scotocercidae
(Bush Warblers and Allies)
Family Sittidae
Family Stenostiridae
(Fairy Flycatchers)
Family Strigidae
(Typical Owls)
Family Sturnidae
Family Sulidae
(Boobies and Gannets)
Family Thinocoridae
Family Thraupidae
(Tanagers and Allies)
Family Threskiornithidae
(Ibises and Spoonbills)
Family Tichodromidae
Family Timaliidae
(Tree-Babblers, Scimitar-Babblers, and Allies)
Family Tityridae
(Tityras and Allies)
Family Trochilidae
Family Trogonidae
Family Turdidae
Family Turnicidae
Family Tyrannidae
(Tyrant Flycatchers)
Family Upupidae
Family Vireonidae
(Vireos, Shrike-Babblers, and Erpornis)
Family Zosteropidae
(White-eyes, Yuhinas, and Allies)