Hawaii Nukupuu (Hemignathus sp.)

The island of Hawai’i today is the home of the Akiapolaau (Hemignathus wilsoni (Rothschild)) (see depiction below), the last of the so-called hetero-billed finches, a group of Hawaiian drepenidine finches with extremely strange bills in which the lower beak is short and, depending on the species, curved up- or downwards, and the upper beak significantly longer and down curved.

This species is depicted below.

The island of Hawai’i, however, once also harbored at least two other hetero-billed finch species, namely the so-called Giant Nukupuu (Hemignathus vorpalis Olson & James), known only by subfossil remains, and the ‘actual’ Nukupuu (Hemignathus aff. lucidus), which is known by a single historical specimen, and which most certainly represented a full and endemic species.

More about this enigmatic form follows below.:

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“Hemignathus lucidus subspp. indet.

A historic specimen of this species, of indeterminate race, was collected on the island of Hawaii by the U.S. Exploring Expedition in 1840 or 1841, but the species was never again taken on that island. A fossil almost certainly of this species was also recovered from sand dune deposits on Molokai.” [2]

The authors treat all Nukupuu forms as a single species, thus this somewhat misleading statement –  the fossil from Moloka’i, of course, is more closely related to the Maui Nukupuu (Hemignathus affinis Rothschild) from Maui.

This sole Hawaii Nukupuu specimen very likely constitutes a sub-adult individual, its plumage appearing to had been in the stage of molting into a yellower garb; the dorsum, the crown and the wings are dull olive with a grayish cast; the underparts are creamy whitish; yellow feathers appear on the lower cheeks and on the midline of the throat and the sides of the upper breast, forming a sort of inverted Y; it also had a faint yellow superciliary line. [1]

This is perhaps one of the most enigmatic of the many Hawaiian drepanidine finches and is shows that these islands have lost an unimaginable precious treasure trove of diversity!

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References:

[1] Storrs Olson & Helen F. James: A specimen of Nuku pu’u (Aves: Drepanidini: Hemignathus lucidus) from the island of Hawai’i. Pacific Science 48(4): 331-338. 1994
[2] Storrs Olson & Helen F. James: Nomenclature of the Hawaiian Akialoas and Nukupuus (Aves: Drepanidini). Proceedings of the Biological Society of Washington 108(3): 373-387. 1995

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edited: 09.10.2020

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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syn. Loxioides kona Greenway, Psittiacirostra palmeri (Rothschild), Psittirostra palmeri (Rothschild), Telespiza palmeri (Rothschild)

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References:

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

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edited: 07.10.2020

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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syn. Loxioides flaviceps (Rothschild), Psittiacirostra flaviceps (Rothschild), Psittirostra flaviceps (Rothschild), Telespiza flaviceps (Rothschild)

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References:

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

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edited: 07.10.2020