Greater Koa Finch
Encyclopedia
The Greater Koa Finch was a species of finch
in the Fringillidae family. It was found only in the Hawaiian Islands
. It has been extinct since the late 19th century.
; 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
, 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
(Rhodocanthis flaviceps), and the Kona Grosbeak
. 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.
, preferring the pods and seeds of koa (Acacia koa). It was also observed eating caterpillar
s and aalii (Dodonaea viscosa
) seeds.
, 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 (Acacia koa), and were logged and replaced with pasture beginning in 1850. Grazing by cattle
inhibited the regeneration of koa forests, while introduced Black Rat
s (Rattus rattus) preyed on young birds. Avian pox (Poxvirus avium) and malaria
(Plasmodium relictum), spread by mosquito
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 forests, as evidenced by the extinction of the other koa finch species (which lived on lower-elevation islands) prior to European contact.
Finch
The true finches are passerine birds in the family Fringillidae. They are predominantly seed-eating songbirds. Most are native to the Northern Hemisphere, but one subfamily is endemic to the Neotropics, one to the Hawaiian Islands, and one subfamily – monotypic at genus level – is found...
in the Fringillidae family. It was found only in the Hawaiian Islands
Hawaiian Islands
The Hawaiian Islands are an archipelago of eight major islands, several atolls, numerous smaller islets, and undersea seamounts in the North Pacific Ocean, extending some 1,500 miles from the island of Hawaii in the south to northernmost Kure Atoll...
. It has been extinct since the late 19th century.
Description
The bird was about 10 in (23 cm) long when fully grown. It was the largest known honey-creeper, although its typical weight is unknown. The bird is sexually dimorphicSexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
; 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
Kona District, Hawaii
Kona is the name of a moku or district on the Big Island of Hawaii in the State of Hawaii. In the current system of administration of Hawaii County, the moku of Kona is divided into North Kona District and South Kona District . The term "Kona" is sometimes used to refer to its largest town,...
District of the island of Hawaii
Hawaii (island)
The Island of Hawaii, also called the Big Island or Hawaii Island , is a volcanic island in the North Pacific Ocean...
, 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
Lesser Koa Finch
The Lesser Koa Finch is an extinct species of finch in the Hawaiian honeycreeper subfamily, Drepanididae.-Description:...
(Rhodocanthis flaviceps), and the Kona Grosbeak
Kona Grosbeak
The Kona Grosbeak is an extinct species of finch in the Hawaiian honeycreeper subfamily, Drepanidinae. The Kona Grosbeak was endemic to naio forests on ʻaʻā lava flows at elevations of near the Kona District on the island of Hawaii...
. 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 granivoreSeed predation
Seed predation, often referred to as granivory, is a type of plant-animal interaction in which granivores feed on the seeds of plants as a main or exclusive food source, in many cases leaving the seeds damaged and not viable...
, preferring the pods and seeds of koa (Acacia koa). It was also observed eating caterpillar
Caterpillar
Caterpillars are the larval form of members of the order Lepidoptera . They are mostly herbivorous in food habit, although some species are insectivorous. Caterpillars are voracious feeders and many of them are considered to be pests in agriculture...
s and aalii (Dodonaea viscosa
Dodonaea viscosa
Dodonaea viscosa is a species of flowering plant in the soapberry family, Sapindaceae, that has a cosmopolitan distribution in tropical, subtropical and warm temperate regions of Africa, the Americas, southern Asia and Australasia.-Description:...
) seeds.
Extinction
The last confirmed sighting was in 1896, although there were sporadic later reports. Like its close relative the Lesser Koa FinchLesser Koa Finch
The Lesser Koa Finch is an extinct species of finch in the Hawaiian honeycreeper subfamily, Drepanididae.-Description:...
, this bird lived in small stretches of mesic
Mesic habitat
In ecology, a mesic habitat is a type of habitat with a moderate or well-balanced supply of moisture, e.g., a mesic forest, a temperate hardwood forest, or dry-mesic prairie. Compared to a dry habitat, a mesic habitat is moister....
forest on the Big Island of Hawaii. These forests were dominated by its preferred food source, koa (Acacia koa), and were logged and replaced with pasture beginning in 1850. Grazing by cattle
Cattle
Cattle are the most common type of large domesticated ungulates. They are a prominent modern member of the subfamily Bovinae, are the most widespread species of the genus Bos, and are most commonly classified collectively as Bos primigenius...
inhibited the regeneration of koa forests, while introduced Black Rat
Black Rat
The black rat is a common long-tailed rodent of the genus Rattus in the subfamily Murinae . The species originated in tropical Asia and spread through the Near East in Roman times before reaching Europe by the 1st century and spreading with Europeans across the world.-Taxonomy:The black rat was...
s (Rattus rattus) preyed on young birds. Avian pox (Poxvirus avium) and malaria
Avian malaria
Avian malaria is a parasitic disease of birds.-Etiology:Avian malaria is most notably caused by Plasmodium relictum, a protist that infects birds in tropical regions...
(Plasmodium relictum), spread by mosquito
Mosquito
Mosquitoes are members of a family of nematocerid flies: the Culicidae . The word Mosquito is from the Spanish and Portuguese for little fly...
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 forests, as evidenced by the extinction of the other koa finch species (which lived on lower-elevation islands) prior to European contact.