Very early European arrivals, ca 1830-40, described seeing birds that might have been the last of the moa but the sightings have never been reliably confirmed. New Zealand has no significant indigenous mammal life. The entire animal ecology consisted of birds, with the moa filling the niche of deer or cattle, and the harpagornis filling the niche of the wolf or tiger. There were ten species. Amongst them were Slender Moa (Dinornis robustus), Great Broad-billed Moa (Euryapteryx gravis) and Lesser Megalapteryx, (Megalapteryx didinus).

It has been long suspected that the species of moa described as Euryapteryx curtus / E. exilis, E. huttonii/ E. crassus, and Pachyornis septentrionalis / P. mappini constituted males and females, respectively. This has been confirmed by analysis for sex-specific genetic markers of DNA extracted from bone material. More interestingly, the former three species of Dinornis: D. giganteus = robustus, D. novaezealandiae and D. struthioides have turned out to be males (struthioides) and females of only two species, one each formerly occurring on New Zealands North Island (D. novaezealandiae) and South Island (D. robustus).

Moa females were larger than males, being up to 150% of the male's size and 280% of their weight. This phenomenon - reverse size dimorphism, is not uncommon amongst ratites, being most pronounced in moa and kiwis. On a side note, the plural form of moa is also moa, as Maori words do not feature plurals.

King Island Emu (Dromaius ater) - Australia 1850
Kangaroo Island Emu (Dromaius baudinianus) - Australia 1827

Ducks, geese and swans

Korean Crested Shelduck (Tadorna cristata) Officially critically endangered due to recent unconfirmed reports. Last confirmed record in 1964.
Réunion Shelduck (Alopochen kervazoi) - Mascarenes 1674
Mauritian Shelduck (Alopochen mauritianus) - Mascarenes 1698
Amsterdam Island Duck (Anas marecula) - Amsterdam Island 1800
Mauritian Duck (Anas theodori) - Mascarenes 1710
Pink-headed Duck (Netta caryophyllacea). Officially critically endangered, but probably extinct. The only area in which it might reasonably still exist is Northern Myanmar due to its remoteness. Reports of Pink-headed Duck continue to be received from this area, but searches have been inconclusive.
Madagascar Pochard (Aythya innotata) Officially critically endangered, but probably extinct: only one, a semi-captive bird at Antananarivo Botanic Gardens, seen alive since 1991, this bird dying in 1992.
Labrador Duck (Camptorhynchus labradorius). This eider-like sea duck was never very common. Although it has been hunted for food, it probably died out because of decline of mussels and shellfish due to pollution. The last one was seen at Elmira, New York, in 1878.
Auckland Islands Merganser (Mergus australis) - Auckland Islands 1902
Nēnē-nui (Branta hylobadistes)
Branta (new species), Hawaiian Giant Goose
Chendytes lawi, flightless diving duck, common to the California Coast, California Channel Islands, and possibly southern Oregon. Lived in the Pleistocene and survived into the Holocene. Appears to have gone extinct about 3000 BP. Remains found in fossil deposits and in early archeological sites. Probably driven to extinction by hunting and loss of habitat.

Quails and relatives

Heath Hen (Tympanuchus cupido cupido), a subspecies of the Greater Prairie-Chicken
New Zealand Quail (Coturnix novaezelandiae) - New Zealand, 1875
Himalayan Quail (Ophrysia superciliosa). Officially critically endangered. Not recorded with certainty since 1876, but thorough surveys are still required, and there is a recent set of possible (though unlikely) sightings around Nainital (India) in 2003. A little-known native name from western Nepal probably refers to this bird, but for various reasons, no survey for Ophrysia has ever been conducted in that country, nor is it generally assumed to occur there (due to the native name being overlooked).

Grebes

Colombian Grebe (Podiceps andinus) Last seen in Colombia in 1977.
Atitlan Grebe (Podilymbus gigas) Last seen in Guatemala in 1986.

Petrels

St Helena Bulwer's Petrel (Bulweria bifax) - St Helena 1550
St Helena Gadfly Petrel (Pterodroma rupinarum) - St Helena 1550
Guadalupe Storm Petrel (Oceanodroma macrodacyla)

Cormorants and related birds

Spectacled Cormorant (Phalacrocorax perspicillatus)

Herons and related birds

New Zealand Little Bittern (Ixobrychus novazelandiae) - New Zealand 1900
Réunion Night Heron (Nycticorax duboisi) - Mascarenes 1674
Mauritius Night Heron (Nycticorax mauritianus) - Mascarenes 1700
Rodrigues Night Heron (Nycticorax megacephalus) - Mascarenes 1761
Réunion Flightless Ibis (Threskiornis solitarius) - Mascarenes 1750. Old descriptions match a flightless Sacred Ibis quite well.
Apteribis, a small flightless ibis from the Hawaiian Islands.

Bird of prey

Argentavis (Argentavis magnificens)
Guadalupe Caracara (Polyborus lutosus)
Haast's Eagle (Harpagornis moorei). Giant eagle (up to 2.6m wingspan) endemic to New Zealand. Extinct approximately 1400 A.D. due to habitat loss and the extinction of its large flightless bird (Moa) prey following human occupation.
Flexiraptor (Pengana robertbolesi), an Australian caracara-like bird that lived 23-16 million years ago in Queensland.

Rails

Chatham Islands Rail (Rallus modestus)
Wake Island Rail (Rallus wakensis)
Tahitian Red-billed Rail (Rallus pacificus)
Ascension Island Rail (Atlantisia elpenor)
Kusaie Island Crake (Porzana monasa)
Hawaiian Rail (Porzana sandwichensis)
Laysan Rail (Porzana palmeri)
Samoan Wood Rail (Gallinula pacifica)
Lord Howe Swamphen (Porphyrio albus)
Mauritius Red Hen (Aphanapteryx bonasia)
Leguat's Gelinote (Aphanapteryx leguatz)

Waders, gulls and auks

Javanese Lapwing (Vanellus macropterus)
White-winged Sandpiper (Prosobonia leucoptera)
Eskimo Curlew (Numenius borealis)
Great Auk (Alca impennis) or (Pinguinus impennis). At 75 centimeters, the flightless Great Auk was the largest of the auks. It was hunted to extinction for food and down for mattresses. The last pair were killed July 3, 1844.

Pigeons and Dodos

Dodo Liverpool Pigeon (Caloenas maculata). Also known as the Spotted Green Pigeon, the only specimen has been in Liverpool Museum since 1851, and was probably collected on a Pacific island for Edward Stanley, 13th Earl of Derby.
Rodrigues Pigeon (Columba rodericana)
Bonin Wood Pigeon (Columba versicolor)
Mauritius Blue Pigeon (Alectroenas nitidissima) Extinct in 19th century.
Forster's Dove of Tanna (Gallicolumba ferruginea)
Marquesas Fruit Pigeon (Ptilinopus mercierii)
Choiseul Crested Pigeon (Microgoura meeki)
Passenger Pigeon (Ectopistes migratorius). The passenger pigeon was once probably the most common bird in the world. It was hunted close to extinction for food and sport in the late 19th century. The last one died in the Cincinnati Zoo in 1914.
Dodo (Raphus cucullatus), called Didus ineptus by Linnaeus. A meter-high flightless bird on Mauritius. Its forest habitat was lost when Dutch settlers moved to the island and the dodo's nests were destroyed by the rats, pigs, and cats the Dutch brought with them. The last specimen was killed in 1681, only 80 years after the arrival of the new predators. Of the 45 bird species originally found on Mauritius, 24 are now extinct.
Rodrigues Solitaire (Pezophaps solitaria). Last seen c.1730.

Parrots

Norfolk Island Kaka (Nestor productus)
Paradise Parrot (Psephotus pulcherrimus)
Society Parakeet (Cyanoramphus ulietanus)
Black-fronted Parakeet (Cyanoramphus zealandicus)
Newton's Parakeet (Psittacula exsul)
Mascarene Parrot (Mascarinus mascarinus)
Broad-billed Parrot (Lophopsittacus mauritianus)
Rodrigues Parrot (Necropsittacus rodericanus)
Cuban Red Macaw (Ara tricolor)
Glaucous Macaw (Anodorhynchus glaucus) Officially critically endangered due to persistent rumors of wild birds, but probably extinct.
Carolina Parakeet (Conuropsis carolinensis). The only parrot native to the eastern US, the Carolina Parakeet was hunted to extinction for its plumage and to prevent damage to crops; it also suffered from destruction of its habitat. The last one died in the Cincinnati Zoo in 1918.

Cuckoos

Delalande's Coucal (Coua delalandei) - Madagascar
St Helena Cuckoo (Nannococcyx psix)

Owls

Reunion Owl (Mascarenotus grucheti)
Mauritius Owl (Mascarenotus sauzieri)
Rodrigues Little Owl (Athene murivora)
Laughing Owl (Sceloglaux albifacies) - New Zealand

Nightjars

Jamaica Least Pauraque (Siphonorhis americanus)

Hummingbirds

Brace's Emerald (Chlorostilbon bracei) - Bahamas 1900
Gould's Emerald (Chlorostilbon elegans) - Jamaica & Bahamas 1900

Kingfishers and related birds

Ryukyu Kingfisher (Halcyon miyakoensis). - a sub-species of Micronesian Kingfisher (Halycon cinnamomina).
St Helena Hoopoe (Upupa antaois) - St Helena 1550

Woodpeckers

Ivory-billed Woodpecker (Campephilus principalis) This species was believed to be extinct since 1987, when the last positive sighting was made in Cuba. However, at least one living male was rediscovered in Arkansas in 2004 and 2005.
Imperial Woodpecker (Campephilus imperialis) This 60-centimeter-long woodpecker is officially listed as critically endangered and is believed to now be extinct.

Passerines

Stephens Island Wren (Xenicus lyalli)
New Zealand Bush Wren (Xenicus longipes)
Bonin Islands Thrush (Zoothera terrestris)
Bay Thrush (Turdus ulietensis) - Society Islands 1774-1850. A completely mysterious bird from Raiatea, now only known from a painting and some descriptions of a (now lost) specimen. Its taxonomic position is unresolvable, although for biogeographic reasons and because of the surviving material, it possibly was a honeyeater. However, with the discovery of fossils of the prehistorically extinct starling Aplonis diluvialis on neighboring Huahine, it seems more likely that this bird also belonged into this genus.
Grand Cayman Thrush (Turdus ravidus)
Kittlitz's Thrush (Zoothera terrestis)
Chatham Island Fernbird (Bowdleria rufescens)
Aldabran Brush Warbler (Nesillas aldabranus)
Lord Howe Gerygone (Gerygone insularis)
Guam Flycatcher (Myiagra freycineti)
Maupiti Monarch (Pomarea pomerea) - Society Islands 1850
South Island Piopio (Turnagra capensis)
North Island Piopio (Turnagra tanagra)
Lord Howe Island White-eye (Zosterops strenua)
Kioea (Chaetoptila angustipluma)
Hawaii 'O'o (Moho nobilis)
Oahu 'O'o (Moho apicalis)
Molokai 'O'o (Moho bishopi)
Kauai 'O'o (Moho braccatus)
Bachman's Warbler (Vermivora bachmanii)
Akialoa (Hemignathus obscurus)
Ula-'ai-hawane (Ciridops anna)
Black Mamo (Drepanis funerea)
Hawaii Mamo (Drepanis pacifica)
Kakawahie (Paroreomyza flammea)
Kona Grosbeak (Psittirostra kona)
Lesser Koa-finch (Rhodacanthus flaviceps)
Greater Koa-finch (Rhodacanthus palmeri)
Greater Amakihi (Viridonia sagittirostris)
Slender-billed Grackle (Quiscalus palustris) - Mexico 1910
Bonin Islands Grosbeak (Chaunoproctus ferreorostris)
Kusaie Island Starling (Aplonis corvina)
Mysterious Starling (Aplonis mavornata)
Norfolk and Lord Howe Starling (Aplonis fusca)
Bourbon Crested Starling (Fregilupus varius)
Rodrigues Starling (Necropsar rodericanus) This bird was considered to be identical with N. rodericanus (which is only known from fossils) and was finally resolved to be based on a misidentified partially albinistic specimen of the Martinique Trembler (Cinclocerthia gutturalis)
Huia (Heteralocha acutirostris)
Po'o-uli (Melamprosops phaeosoma) - the last known bird has died in captivity at 28 November 2004