Hawaiian honeycreeper

Hawaiian honeycreepers are small passerine birds endemic to Hawaiʻi. Some authorities categorize this group as a family Drepanididae, but more recently they are usually placed as a subfamily Drepanidinae of the finch family Fringillidae.

The group is divided into three tribes: Some unusual forms never seen alive by scientists, such as Xestospiza or Vangulifer, cannot easily be placed into any group.
 * Psittirostrini (Hawaiian finches), seedeaters with thick finch-like bills and songs like those of cardueline finches.
 * Hemignathini (Hawaiian creepers and allies, including nukupuʻus). These are generally green-plumaged birds with thin bills which feed on nectar and insects
 * Drepanidini (Mamos, ʻIʻiwi and allies). These are birds often with red plumage. They are nectar-feeders and their songs contain nasal squeaks and whistles.

The male Hawaiian honeycreepers are more brightly coloured than the females in the Psittirostrini, but in the Hemignathini, they often look very similar. The flowers of the native plant Metrosideros polymorpha (ʻōhiʻa lehua) are favoured by a number of nectar-eating honeycreepers.

The wide range of bills in this group, from thick finch-like bills to slender downcurved bills for probing flowers have arisen through adaptive radiation, where an ancestral finch has evolved to fill a large number of ecological niches. Some 15 forms of Hawaiian honeycreeper have become extinct in the recent past, many more since the arrival of the Polynesians who introduced the first rats and in some cases started destroying habitat for agriculture (James & Olson 1991, Olson & James 1991). The recent extinctions are due to the introduction of other rodent species and the mongoose, habitat destruction and avian malaria and fowlpox. However, conservation efforts are attempting to neutralize these threats.

Genera and species
The term "prehistoric" indicates species that went extinct between the initial human settlement of Hawaiʻi (i.e., from the late 1st millennium AD on) and European contact in 1778.

FAMILY DREPANIDIDAE 
 * Genus Telespiza - finch-like, granivores, opportunistic scavengers
 * Nihoa Finch, Telespiza ultima
 * Laysan Finch, Telespiza cantans
 * Kauaʻi Finch, Telespiza persecutrix - prehistoric
 * Maui Nui Finch, Telespiza ypsilon - prehistoric
 * Genus Psittirostra - slightly hooked bill, ʻieʻie fruit specialist
 * ʻŌʻū, Psittirostra psittacea - probably extinct (late 1990s?)
 * Genus Dysmorodrepanis - pincer-like bill, possibly snail specialist
 * Lanaʻi Hookbill, Dysmorodrepanis munroi - extinct (1918)
 * Genus Loxioides - finch-like, Fabales seed specialists
 * Palila, Loxioides bailleui
 * Pila's Palila, Loxioides kikuichi - prehistoric; possibly survived to the early 18th century
 * Genus Rhodacanthis - finch-like, koa seed specialists
 * Lesser Koa-finch, Rhodacanthis flaviceps - extinct (1891)
 * Greater Koa-finch, Rhodacanthis palmeri - extinct (1896)
 * Scissor-billed Koa-finch, Rhodacanthis forfex - prehistoric
 * Primitive Koa-finch, Rhodacanthis litotes - prehistoric
 * Genus Chloridops - thick-billed, naio and other hard seed specialist
 * Kona Grosbeak, Chloridops kona - extinct (1894)
 * Oʻahu Grosbeak, Chloridops wahi - prehistoric
 * Giant ("King Kong") Grosbeak, Chloridops regiskongi - prehistoric
 * Genus Orthiospiza - large weak bill, possibly soft seed or fruit specialist?
 * Highland Finch, Orthiospiza howarthi - prehistoric
 * Genus Xestospiza - cone-shaped bills, possibly insectivores
 * Cone-billed Finch, Xestospiza conica - prehistoric
 * Ridge-billed Finch, Xestospiza fastigialis - prehistoric
 * Genus Pseudonestor - parrot-like bill, probes rotting wood for insect larvae
 * Maui Parrotbill, Pseudonestor xanthophrys
 * Genus Hemignathus - pointed or long and downcurved bills, insectivores or nectarivores
 * Common ʻAmakihi or Hawaiʻi ʻAmakihi, Hemignathus virens
 * Oʻahu ʻAmakihi, Hemignathus flavus
 * Kauaʻi ʻAmakihi, Hemignathus kauaiensis
 * Nukupuʻu, Hemignathus lucidus - possibly extinct (c.2000?)
 * Greater ʻAmakihi, Hemignathus sagittirostris - extinct (1901)
 * Giant ʻAmakihi, Hemignathus vorpalis - prehistoric
 * (Sub)Genus Magumma
 * ʻAnianiau, Hemignathus parvus or Magumma parva
 * (Sub)Genus Akialoa
 * Hawaiʻi ʻAkialoa, Hemignathus obscurus or Akialoa obscura - extinct (1940)
 * Maui Nui ʻAkialoa, Hemignathus lanaiensis or Akialoa lanaiensis - extinct (1892)
 * Oʻahu ʻAkialoa, Hemignathus ellisianus or Akialoa ellisiana - extinct (1940)
 * Kauaʻi ʻAkialoa, Hemignathus stejnegeri or Akialoa stejnegeri - extinct (1969)
 * Hoopoe-billed ʻAkialoa, Hemignathus upupirostris or Akialoa upupirostris - prehistoric
 * (Sub)Genus Heterorhynchus
 * ʻAkiapolaʻau, Hemignathus munroi or Heterorhynchus wilsoni
 * Genus Oreomystis - short pointed bills, browsers
 * ʻAkikiki, Oreomystis bairdi
 * Hawaiʻi Creeper, Oreomystis mana
 * Genus Paroreomyza - similar to Oreomystis
 * Maui Nui ʻAlauahio or Maui ʻAlauahio, Paroreomyza montana
 * Lanaʻi ʻAlauahio, Paroreomyza montana montana - extinct (1937)
 * Kakawahie, Paroreomyza flammea - extinct (1963)
 * Oʻahu ʻAlauahio, Paroreomyza maculata - possibly extinct (early 1990s?)
 * Genus Vangulifer - flat rounded bills, possibly caught flying insects
 * Strange-billed Finch, Vangulifer mirandus - prehistoric
 * Thin-billed Finch, Vangulifer neophasis - prehistoric
 * Genus Aidemedia - straight thin bills, insectivores
 * Oʻahu Icterid-like Gaper, Aidemedia chascax - prehistoric
 * Sickle-billed Gaper, Aidemedia zanclops - prehistoric
 * Maui Nui Icterid-like Gaper, Aidemedia lutetiae - prehistoric
 * Genus Loxops - small pointed bills with the tips offset a little horizontally, insectivores
 * ʻAkekeʻe, Loxops caeruleirostris
 * ʻAkepa, Loxops coccineus
 * Maui ʻAkepa, Loxops coccineus ochraceus - extinct (1988)
 * Oʻahu ʻAkepa, Loxops coccineus wolstenholmei - extinct (1990s)
 * Genus Ciridops - finch-like, fed on loulu fruits etc.
 * ʻUla-ʻai-Hawane, Ciridops anna - extinct (1892 or 1937)
 * Stout-legged Finch, Ciridops tenax - prehistoric
 * Genus Vestiaria - downcurved bill, nectarivore
 * ʻIʻiwi, Vestiaria coccinea
 * Genus Drepanis - downcurved bills, nectarivores
 * Hawaiʻi Mamo, Drepanis pacifica - extinct (1898)
 * Black Mamo, Drepanis funerea - extinct (1907)
 * Genus Palmeria - thin bill, nectarivore, especially ʻohiʻa
 * ʻAkohekohe, Palmeria dolei
 * Genus Himatione - thin bill, nectarivore
 * ʻApapane, Himatione sanguinea
 * Laysan ʻApapane, Himatione (sanguinea) freethi - extinct (1923)
 * Genus Melamprosops - short pointed bill, browser and snail specialist
 * Poʻo-uli, Melamprosops phaeosoma - probably extinct (November 28, 2004?)

Several other prehistoric forms are undescribed, as they are known only from very fragmentary fossil remains insufficient to deterine taxonomic affiliation. These include one taxon from Oʻahu, at least 3 from Maui, and possibly 2 enigmatic passerines from Kauaʻi which may or may not be drepanidids.