Rhodacanthis is an extinct

Extinction

In biology and ecology, extinction is the end of an organism or of a group of organisms , normally 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 recover may have been lost before this point...

 genus of finch

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...

es in the Hawaiian honeycreeper

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...

 subfamily

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

, Drepanidinae. All four species were endemic to 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...

. Members of this genus were granivores

Seed 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...

, with bills adapted to the seed

Seed

A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...

s and pods of legumes. The two species that became extinct in the 1890s, R. flaviceps and R. palmeri, inhabited upper elevation mesic forests dominated by koa (Acacia koa) on 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...

. Both were large birds; R. flaviceps measured 19 cm (7.5 in), while R. palmeri was 23 cm (9.1 in) in length. The combination of a giant bill with brightly-colored plumage

Plumage

Plumage refers both to the layer of feathers that cover a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage vary between species and subspecies and can also vary between different age classes, sexes, and season. Within species there can also be a...

 (yellow for R. flaviceps, orange for R. palmeri) gave the males a very striking appearance. Koa seeds were the preferred food for the two species, but 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 were taken if necessary. The two prehistoric species, R. forfex

Scissor-billed Koa-finch

The Scissor-billed Koa-finch, or Scissor Finch is an extinct species of finch in the Hawaiian honeycreeper subfamily, Drepanididae. Of the four species in the genus Rhodacanthis, the Scissor-billed Koa Finch and the Primitive Koa-finch became extinct before the arrival of the first Europeans to...

and R. litotes

Primitive Koa-finch

The Primitive Koa-finch is a species of finch in the Hawaiian honeycreeper subfamily, Drepanididae. It was endemic to Hawaii. Of the four species in the genus Telespiza, it and the Scissor-billed Koa-finch became extinct before the arrival of the first Europeans to Hawaii in 1778...

, were denizens of more lowland tropical dry forests

Hawaiian tropical dry forests

The Hawaiian tropical dry forests are a tropical dry broadleaf forest ecoregion in the Hawaiian Islands. They cover an area of on the leeward side of the main islands and the summits of Niihau and Kahoolawe. These forests are either seasonal or sclerophyllous. Annual rainfall is less than and...

 and shrublands

Hawaiian tropical low shrublands

The Hawaiian tropical low shrublands are a tropical savanna ecoregion in the Hawaiian Islands. These shrublands cover an area of in the leeward lowlands of the main islands and most of the smaller islands, including the Northwestern Hawaiian Islands. The ecoregion includes both grasslands and...

 on Kauai

Kauai

Kauai or Kauai, known as Tauai in the ancient Kaua'i dialect, is geologically the oldest of the main Hawaiian Islands. With an area of , it is the fourth largest of the main islands in the Hawaiian archipelago, and the 21st largest island in the United States. Known also as the "Garden Isle",...

, Maui

Maui

The island of Maui is the second-largest of the Hawaiian Islands at and is the 17th largest island in the United States. Maui is part of the state of Hawaii and is the largest of Maui County's four islands, bigger than Lānai, Kahoolawe, and Molokai. In 2010, Maui had a population of 144,444,...

, and Oahu

Oahu

Oahu or Oahu , known as "The Gathering Place", is the third largest of the Hawaiian Islands and most populous of the islands in the U.S. state of Hawaii. The state capital Honolulu is located on the southeast coast...

. It is speculated that koaia (Acacia koaia

Acacia koaia

Acacia koaia, known as koaia or koaie in Hawaiian, is a tree in the pea family, Fabaceae, that is endemic to Hawaii. It is closely related to koa , and is sometimes considered to be the same species...

) was an important food source for both species, as their range did not overlap with that of koa. Kanaloa (Kanaloa spp.) pods 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:...

) berries

Berry

The botanical definition of a berry is a fleshy fruit produced from a single ovary. Grapes are an example. The berry is the most common type of fleshy fruit in which the entire ovary wall ripens into an edible pericarp. They may have one or more carpels with a thin covering and fleshy interiors....

  were probably also eaten in addition to the occasional caterpillar.

Species

• Rhodacanthis flaviceps Rothschild
  Walter Rothschild, 2nd Baron Rothschild
  Lionel Walter Rothschild, 2nd Baron Rothschild, Baron de Rothschild FRS , a scion of the Rothschild family, was a British banker, politician, and zoologist.-Biography:...
  
  , 1892 - Lesser Koa-Finch (extinct, 1891)
• Rhodacanthis forfex James & Olson
  Storrs L. Olson
  Storrs Lovejoy Olson is an American biologist and ornithologist from the Smithsonian Institution. He is one of the world's foremost avian paleontologists....
  
  , 2005 - Scissor-billed Koa-finch
  Scissor-billed Koa-finch
  The Scissor-billed Koa-finch, or Scissor Finch is an extinct species of finch in the Hawaiian honeycreeper subfamily, Drepanididae. Of the four species in the genus Rhodacanthis, the Scissor-billed Koa Finch and the Primitive Koa-finch became extinct before the arrival of the first Europeans to...
  
   (prehistoric)
• Rhodacanthis litotes James & Olson, 2005 - Primitive Koa-finch
  Primitive Koa-finch
  The Primitive Koa-finch is a species of finch in the Hawaiian honeycreeper subfamily, Drepanididae. It was endemic to Hawaii. Of the four species in the genus Telespiza, it and the Scissor-billed Koa-finch became extinct before the arrival of the first Europeans to Hawaii in 1778...
  
   (prehistoric)
• Rhodacanthis palmeri Rothschild, 1892 - Greater Koa-Finch (extinct, 1896)