Narrow-billed Kioea (Chaetoptila sp.)  

The Narrow-billed Kioea is known from subfossil bones that were found on the island of Maui, Hawaiian Islands.

The species had a much narrower bill than the Hawaiian Kioe, with which it occurred sympatrically (at least if the form known as Chaetoptila sp. ‘Maui Nui’ indeed turns out to be identical with this species) [1]. 

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References:  

[1] S. L. Olson; H. F. James: Descriptions of thirty-two new species of birds from the Hawaiian Islands: Part II. Passeriformes. Ornithological Monographs 45: 1-91. 1991

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edited: 13.09.2020