The lesser koa finch (''Rhodacanthis flaviceps'') is an extinct species of Hawaiian honeycreeper in the subfamily Carduelinae of the family Fringillidae. It was

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

to the island of Hawaiʻi.

Description

The only specimens of the lesser koa finch ever caught were a family group with members of different ages and sex, ideal for study.George C. Munro. (1944) The males were apparently golden-yellow with olive green on the breast and belly. The females were almost indistinguishable from the species' larger relative, the greater koa finch (''Rhodacanthis palmeri''), other than the fact that the former were slightly darker in color. The juveniles were somewhat mottled on the belly, similar to the females.

Distribution and habitat

The lesser koa finch was

to the island of Hawaiʻi. This species was recorded in upland koa ('' Acacia koa'') forests, but likely inhabited lowland habitat until before or shortly after the time of western contact in 1778. The

IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is an inventory of the global conservation status and extinction risk of biological ...

says, "This or a similar species is also known from the fossil record of O'ahu and

Maui Maui (; Hawaiian language, Hawaiian: ) is the second largest island in the Hawaiian archipelago, at 727.2 square miles (1,883 km2). It is the List of islands of the United States by area, 17th-largest in the United States. Maui is one of ...

," citing a 1991 paper. This apparently refers to the primitive koa finch (''Rhodacanthis litotes''), a similarly sized species known from fossils on Oʻahu and

, described as a new species in 2005.

Behavior

Its life cycle and feeding habits apparently centered around the koa plant from which it got nectar and fruit (and for which it was named). The koa also provided refuge for small flocks of the finch as it avoided people and the noon high sun. It was seen congregating with its larger relative, the greater koa finch (''Rhodacanthis palmeri''). Several specimens were collected and sent to London, Cambridge, New York, Philadelphia, and Berlin.

Extinction

The extinction of this species and other koa finches seems to have been caused by

habitat destruction Habitat destruction (also termed habitat loss or habitat reduction) occurs when a natural habitat is no longer able to support its native species. The organisms once living there have either moved elsewhere, or are dead, leading to a decrease ...

, and not by climatic variation nor mosquito-vectored diseases. Koa finches were likely driven out of lowland habitat and into upland refugia before or shortly after the time of western contact in 1778. On the island of Hawaiʻi, koa finches persisted until the late 19th century, when their upland refugium was degraded by logging, ranching, and intensified predation by the

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 ...

. The lesser koa finch was last recorded in 1891.

References

* Bryson, Bill. A Short History of Nearly Everything. 1st ed. 1 vol. New York, NY: Broadway Books, 2004. 476. Print. * Munro, George C. Birds of Hawaii. {{Taxonbar, from=Q1065066 Bird extinctions since 1500 Rhodacanthis Hawaiian honeycreepers Extinct birds of Hawaii Birds described in 1892 Taxonomy articles created by Polbot