Hawaiian honeycreeper

Hawaiian honeycreepers are small, passerine birds endemic to Hawaii. Some authorities still categorize this group as a family Drepanididae, but in recent years, most authorities consider them a subfamily, Drepanidinae, of Fringillidae, the finch family. The entire group is also called "Drepanidini" in treatments where buntings and American sparrows (Emberizidae) are included in the finch family; this term is preferred for just one subgroup of the birds today.

Classification
The group is divided into three tribes, but only very provisionally so. Several taxa appear to be too basal to really place into one of these, and others are best considered incertae sedis. Some unusual forms never seen alive by scientists, such as Xestospiza or Vangulifer, cannot easily be placed into any group.

Psittirostrini
Members of Psittirostrini, known as "Hawaiian finches", are granivorous with thick finch-like bills, and songs like those of cardueline finches. The group once covered the islands. Finch-billed drepanids include the Laysan finch, the Nihoa finch, the Maui parrotbill and the palila, which may be the last remaining species left alive in this group. Extinct species include the four Koa finches, the Ōū, and the Lānai Hookbill.

Hemignathini
Hemignathini includes the Hawaii creeper and its allies, such as the nukupuu. These are generally green-plumaged birds with thin bills, and feed on nectar and insects. Members of this group usually have green, yellow, orange, red, and grey feathers.

Drepanidini
Species in the tribe Drepanidini are nectarivorous, and their songs contain nasal squeaks and whistles. Members of this group often have red black, yellow, white and orange plumage. It includes the iiwi.

Characteristics
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 ōhia lehua (Metrosideros polymorpha) are favoured by a number of nectarivorous honeycreepers. Many species of this subfamily have been noted to have a plumage odor that has been termed the "Drepanidine odor", and is suspected to have a role in making the bird distasteful to predators.

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 20 species of Hawaiian honeycreeper have become extinct in the recent past, and many more in earlier times, between the arrival of the Polynesians who introduced the first rats, chickens, pigs, and dogs, and hunted and converted habitat for agriculture.

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

SUBFAMILY DREPANIDINAE 
 * Tribe Drepanidini
 * Genus Ciridops Newton, 1892 - finch-like, fed on fruit of Pritchardia species
 * Ciridops anna Dole, 1879 - Ula ai hāwane (extinct, 1892 or 1937)
 * Ciridops tenax Olson & James, 1991 Stout-legged Finch (prehistoric)
 * Genus Drepanis Temminck, 1820 - downcurved bills, nectarivores
 * Drepanis funerea Newton, 1894 - Black Mamo (extinct, 1907)
 * Drepanis pacifica Gmelin, 1788 - Hawaii Mamo (extinct, 1898)
 * Genus Himatione - thin-billed nectarivore
 * Himatione sanguinea Gmelin, 1788 - Apapane
 * Himatione sanguinea freethi - Laysan Apapane (extinct, 1923)
 * Genus Melamprosops Casey & Jacobi, 1974 - short pointed bill, browser and snail specialist
 * Melamprosops phaeosoma Casey & Jacobi, 1974 - Poouli (possibly extinct, November 28, 2004?)
 * Genus Palmeria Rothschild, 1893 - thin-billed nectarivore, favors Metrosideros polymorpha
 * Palmeria dolei Wilson, 1891 - Ākohekohe (thought to be extinct, rediscovered in 1945)
 * Genus Vestiaria Jarocki, 1821 - downcurved-bill nectarivore
 * Vestiaria coccinea Forster, 1780 - Iiwi
 * Tribe Hemignathini
 * Genus Aidemedia Olson & James, 1991 - straight thin bills, insectivores
 * Aidemedia chascax Olson & James, 1991 - Oahu Icterid-like Gaper (prehistoric)
 * Aidemedia lutetiae Olson & James, 1991 - Maui Nui Icterid-like Gaper (prehistoric)
 * Aidemedia zanclops Olson & James, 1991 - Sickle-billed Gaper (prehistoric)
 * Genus Hemignathus Lichtenstein, 1839 - pointed or long and downcurved bills, insectivorous or nectarivorous
 * Hemignathus flavus Bloxam, 1827 - Oahu Amakihi
 * Hemignathus kauaiensis Pratt, 1989 - Kauai Amakihi
 * Hemignathus lucidus Lichtenstein, 1839 - Nukupuu (possibly extinct, late 1990s?)
 * Hemignathus lucidus affinis - Maui Nukupuu (extinct, 1995–1998)
 * Hemignathus lucidus hanapepe - Kauai Nukupuu (extinct, 1998)
 * Hemignathus lucidus lucides - Oahu Nukupuu (extinct, 1837)
 * Hemignathus sagittirostris Rothschild, 1892 - Greater Amakihi (extinct, 1901)
 * Hemignathus virens Cabanis, 1851 - Common Amakihi
 * Hemignathus vorpalis James & Olson, 2003 - Giant Amakihi (prehistoric)
 * (Sub)Genus Akialoa
 * Hemignathus ellisianus or Akialoa ellisiana Gray, 1859 - Oahu Akialoa (extinct, 1940)
 * Hemignathus lanaiensis or Akialoa lanaiensis Rothschild, 1893 - Maui Nui Akialoa (extinct, 1892)
 * Hemignathus obscurus or Akialoa obscura Cabanis, 1889 - Hawaii Akialoa (extinct, 1940)
 * Hemignathus stejnegeri or Akialoa stejnegeri Wilson, 1889 - Kauai Akialoa (extinct, 1969)
 * Hemignathus upupirostris or Akialoa upupirostris - Hoopoe-billed Akialoa (prehistoric)
 * (Sub)Genus Heterorhynchus
 * Hemignathus munroi or Heterorhynchus wilsoni Pratt, 1979 - Akiapolaau
 * (Sub)Genus Magumma
 * Hemignathus parvus or Magumma parva Stejneger, 1887 - Anianiau
 * Genus Loxops - small pointed bills with the tips offset a little horizontally, insectivores
 * Loxops caeruleirostris Wilson, 1890 - Akekee
 * Loxops coccineus Gmelin, 1789 - Ākepa
 * Loxops coccineus coccineus - Hawaii Ākepa
 * Loxops coccineus ochraceus - Maui Ākepa (extinct, 1988)
 * Loxops coccineus wolstenholmei - Oahu Ākepa (extinct, 1990s)
 * Genus Oreomystis Wilson, 1891 - short pointed bills, browsers
 * Oreomystis bairdi Stejneger, 1887 - Akikiki
 * Oreomystis mana Wilson, 1891 - Hawaii Creeper
 * Genus Paroreomyza - similar to Oreomystis
 * Paroreomyza montana Wilson, 1890 - Maui Nui Alauahio
 * Paroreomyza montana montana - Lānai Alauahio (extinct, 1937)
 * Paroreomyza flammea Wilson, 1889 - Molokai Creeper or Kākāwahie (extinct, 1963)
 * Paroreomyza maculata Cabanis, 1850 - Oahu Alauahio (possibly extinct, early 1990s?)
 * Genus Vangulifer - flat rounded bills, possibly caught flying insects
 * Vangulifer mirandus - Strange-billed Finch (prehistoric)
 * Vangulifer neophasis - Thin-billed Finch (prehistoric)
 * Tribe Psittirostrini
 * Genus Chloridops Wilson, 1888 - thick-billed, Myoporum sandwicense and other hard seed specialist
 * Chloridops kona Wilson, 1888 - Kona Grosbeak (extinct, 1894)
 * Chloridops regiskongi - Giant ("King Kong") Grosbeak (prehistoric)
 * Chloridops wahi - Wahi Grosbeak (prehistoric)
 * Genus Dysmorodrepanis Perkins, 1919 - pincer-like bill, possibly snail specialist
 * Dysmorodrepanis munroi Perkins, 1919 - Lānai Hookbill (extinct, 1918)
 * Genus Loxioides Oustalet, 1877 - finch-like, Fabales seed specialists
 * Loxioides bailleui Oustalet, 1877 - Palila
 * Loxioides kikuichi Olson & James, 2006 - Kauai Palila (prehistoric, possibly survived to the early 18th century)
 * Genus Orthiospiza - large weak bill, possibly soft seed or fruit specialist?
 * Orthiospiza howarthi James & Olson, 1991 - Highland Finch (prehistoric)
 * Genus Pseudonestor - parrot-like bill, probes decomposing wood for insect larvae
 * Pseudonestor xanthophrys Rothschild, 1893 - Maui Parrotbill (thought to be extinct, rediscovered in 1945)
 * Genus Psittirostra - slightly hooked bill, Freycinetia arborea fruit specialist
 * Psittirostra psittacea Gmelin, 1789 - Ōū (probably extinct, 1998?)
 * Genus Rhodacanthis - large-billed legume specialists
 * Rhodacanthis flaviceps Rothschild, 1892 - Lesser Koa-finch (extinct, 1891)
 * Rhodacanthis forfex James & Olson, 2005 - Scissor-billed Koa-finch (prehistoric)
 * Rhodacanthis litotes James & Olson, 2005 - Primitive Koa-finch (prehistoric)
 * Rhodacanthis palmeri Rothschild, 1892 - Greater Koa-finch (extinct, 1896)
 * Genus Telespiza Wilson, 1890 - finch-like, granivores, opportunistic scavengers
 * Telespiza cantans Wilson, 1890 - Laysan Finch
 * Telespiza persecutrix James & Olson, 1991 - Kauai Finch (prehistoric)
 * Telespiza ultima Bryan, 1917 - Nihoa Finch
 * Telespiza ypsilon James & Olson, 1991 - Maui Nui Finch (prehistoric)
 * Genus Xestospiza James & Oslon, 1991 - cone-shaped bills, possibly insectivores
 * Xestospiza conica James & Olson, 1991 - Cone-billed Finch (prehistoric)
 * Xestospiza fastigialis James & Olson, 1991 - Ridge-billed Finch (prehistoric)

Other references

 * Groth, J. G. 1998. Molecular phylogeny of the cardueline finches and Hawaiian honeycreepers. Ostrich, 69: 401.