The greater koa finch (''Rhodacanthis palmeri'') was a species of

finch The true finches are small to medium-sized passerine birds in the family Fringillidae. Finches have stout conical bills adapted for eating seeds and nuts and often have colourful plumage. They occupy a great range of habitats where they are usua ...

in the family

Fringillidae The true finches are small to medium-sized passerine birds in the family Fringillidae. Finches have stout conical bills adapted for eating seeds and nuts and often have colourful plumage. They occupy a great range of habitats where they are usua ...

. It was found only in the

Hawaiian Islands The Hawaiian Islands ( haw, Nā Mokupuni o Hawai‘i) are an archipelago of eight major islands, several atolls, and numerous smaller islets in the North Pacific Ocean, extending some from the island of Hawaii in the south to northernmost Kur ...

. It has been

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

since the late 19th century.

Description

The bird was about 7–8 in (18–20 cm) long when fully grown. It was the largest known honey-creeper, although its typical weight is unknown. The bird was

sexually dimorphic Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most ani ...

; the male was brilliant scarlet-orange on head, neck, and breast, with lighter orange on its bottom, and olive brown with orange touches on back, wings, and tail; however, the female was brownish olive, and somewhat lighter below. It had a thick black bill which allowed it to break open seed pods that were found in the trees. In historical times, its range was largely confined to the Kona District of the island of

Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only stat ...

, although it was observed in the Kīlauea area in 1895. It was much more widespread prior to the arrival of humans in Hawaii, and related species lived on other islands. In Kona, it co-occurred with the closely related

lesser koa finch The lesser koa finch (''Rhodacanthis flaviceps'') is an extinct species of Hawaiian honeycreeper. Description The only specimens of the lesser koa finch ever caught were a family group with members of different ages and genders, ideal for stu ...

(''Rhodocanthis flaviceps''), and the

Kona grosbeak The Kona grosbeak (''Chloridops kona'') is an extinct species of Hawaiian honeycreeper. The Kona grosbeak was endemic to naio (''Myoporum sandwicense'') forests on ʻaʻā lava flows at elevations of near the Kona District on the island of Hawa ...

. The lesser and greater koa finches were once thought by scientists to be the minimum and maximum growth of a single species of koa finch.

Diet

The greater koa finch was a

granivore Seed predation, often referred to as granivory, is a type of plant-animal interaction in which granivores (seed predators) feed on the seeds of plants as a main or exclusive food source,Hulme, P.E. and Benkman, C.W. (2002) "Granivory", pp. 132 ...

, preferring the pods and seeds of koa (''

Acacia koa ''Acacia koa'' or commonly known as koa is a species of flowering tree in the family Fabaceae. It is endemic to the Hawaiian Islands, where it is the second most common tree. The highest populations are on Hawaii, Maui and Oahu. Name The name ...

''). It was also observed eating

caterpillar Caterpillars ( ) are the larval stage of members of the order Lepidoptera (the insect order comprising butterflies and moths). As with most common names, the application of the word is arbitrary, since the larvae of sawflies (suborder Sym ...

s and aalii (''

Dodonaea viscosa ''Dodonaea viscosa'', also known as the broadleaf hopbush, is a species of flowering plant in the ''Dodonaea'' (hopbush) genus that has a cosmopolitan distribution in Tropics, tropical, Subtropics, subtropical and warm temperate regions of Africa ...

'') seeds.

Extinction

The last confirmed sighting was in 1896, although there were sporadic later reports. Like its close relative the

, this bird lived in small stretches of mesic forest on the Big Island of Hawaii. These forests were dominated by its preferred food source, koa (''

''), and were logged and replaced with pasture beginning in 1850. Grazing by

cattle Cattle (''Bos taurus'') are large, domesticated, cloven-hooved, herbivores. They are a prominent modern member of the subfamily Bovinae and the most widespread species of the genus ''Bos''. Adult females are referred to as cows and adult mal ...

inhibited the regeneration of koa forest, while introduced

black rat The black rat (''Rattus rattus''), also known as the roof rat, ship rat, or house rat, is a common long-tailed rodent of the stereotypical rat genus ''Rattus'', in the subfamily Murinae. It likely originated in the Indian subcontinent, but is n ...

s (''Rattus rattus'') preyed on young birds.

Avian pox ''Avipoxvirus'' (avian pox) is a genus of viruses within the family ''Poxviridae''. ''Poxviridae'' is the family of viruses which cause the afflicted organism to have poxes as a symptom. Poxviruses have generally large genomes, and other such ex ...

(''Poxvirus avium'') and

malaria Malaria is a mosquito-borne infectious disease that affects humans and other animals. Malaria causes symptoms that typically include fever, tiredness, vomiting, and headaches. In severe cases, it can cause jaundice, seizures, coma, or death. S ...

(''Plasmodium relictum''), spread by

mosquito Mosquitoes (or mosquitos) are members of a group of almost 3,600 species of small flies within the family Culicidae (from the Latin ''culex'' meaning " gnat"). The word "mosquito" (formed by ''mosca'' and diminutive ''-ito'') is Spanish for "li ...

es, may have also been a factor. However, even before these issues became important, the koa finches were probably already living in marginal habitat due to the loss of lowland koa forest, as evidenced by the extinction of the other koa finch species (which lived on lower-elevation islands) prior to European contact.

References

{{Taxonbar, from=Q1078624 Rhodacanthis Endemic birds of Hawaii Extinct birds of Hawaii Bird extinctions since 1500 Birds described in 1892 Taxonomy articles created by Polbot