Tag Archives: Rhodacanthis

Rhodacanthis forfex James & Olson

Scissor-billed Koa-Finch (Rhodacanthis forfex)

The Scissor-billed Koa Finch is known only by subfossil remains, found on the islands of Kaua’i and Maui, the species clearly also occurred on the islands in between.

The species disappeared shortly after the arrival of the first human settlers on the Hawaiian Islands.

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References:

[1] Helen F. James; Storrs L. Olson: The diversity and biogeography of koa-finches (Drepanidini: Rhodacanthis), with descriptions of two new species. Zoological Journal of the Linnean Society 144: 527-541. 2005

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edited: 07.10.2020

Rhodacanthis palmeri Rothschild

Greater Koa-Finch (Rhodacanthis palmeri)

The Greater Koa Finch, named hopue by the native Hawaiians, was already nearly extinct when it was discovered by European ornithologists.

The species originally inhabited dry lowland forests that were dominated by the endemic koa acacias (Acacia koa A. Gray) whose seed pods and seeds apparently were its main food source, it furthermore fed on the seeds of the native ‘a’ali’i (Dodonaea viscosa Jacq.) and caterpillars. Most of the lowland forests had already been destroyed by the Hawaiian natives long before the first European settlers arrived, and the finches were restricted to the small remains in the northern Kona District in the western part of Hawai’i.

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When alive, Greater Koa Finch was by far the largest of the Hawaiian endemic drepanidine finches; it reached a size of 23 cm; the males had bright scarlet-orange heads and breasts, while the females were more or less completely plain green colored.

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References:

[1] H. Douglas Pratt: The Hawaiian Honeycreepers: Drepanidinae. Oxford Univ. Pr. 2005

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Depiction from: ‘W. Rothschild: The Avifauna of Laysan and the neighbouring islands with a complete history to date of the birds of the Hawaiian possession. 1893-1900’

(public domain)

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edited: 07.10.2020

Rhodacanthis flaviceps Rothschild

Lesser Koa-Finch (Rhodacanthis flaviceps)

The Lesser Koa Finch was already almost extinct when it was discovered by European ornithologists in 1892; it was only found only once, in its type locality, a place called Pu’u Lehua in the lowlands of the northern Kona District almost in the middle of the western coast of Hawai’i.

It was found in mixed flocks with Greater Koa-Finches (Rhodacanthis palmeri Rothschild) feeding on the seeds of koa acacias (Acacia koa A. Gray), eight specimens were taken back than by bird collectors, which did not recognize that they were dealing with two distinct species at that time. [1]

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The species reached a size of about 19 cm; males had bright yellow heads and bellies, while females were nearly completely green colored. [1]

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The Lesser Koa-Finch was never found again since so was probably extinct already shortly after. [1]

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References:

[1] H. Douglas Pratt: The Hawaiian Honeycreepers: Drepanidinae. Oxford Univ. Pr. 2005

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Depiction from: ‘W. Rothschild: The Avifauna of Laysan and the neighbouring islands with a complete history to date of the birds of the Hawaiian possession. 1893-1900’ 

(public domain)

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edited: 07.10.2020

Rhodacanthis litotes James & Olson

Primitive Koa-Finch (Rhodacanthis litotes)

The Primitive Koa Finch was described in 2005 based on subfossil remains that were found on the islands of Maui and O’ahu, Hawaiian Islands, the species clearly also occurred on the islands in between.

At least on Maui the species occurred in sympatry with another closely related species, the Scissor-billed Koa Finch (Rhodacanthis forfex James & Olson), a constellation which is known also from the island of Hawai’i, where two other congeneric species, the Lesser- (Rhodacanthis flaviceps Rothschild) and the greater Koa-Finch (Rhodacanthis palmeri Rothschild) formed mixed flocks feeding together.

The primitive Koa-Finch aka. Oahu Koa-Finch disappeared before the first Europeans arrived on the Hawaiian Islands. 

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References:

[1] Helen F. James; Storrs L. Olson: The diversity and biogeography of koa-finches (Drepanidini: Rhodacanthis), with descriptions of two new species. Zoological Journal of the Linnean Society 144: 527-541. 2005

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edited: 07.10.2020