I'iwi is perfectly complemented by the black wings and tail. Their long decurved salmon-colored bills are specialized for sipping nectar from tubular flowers. Although the sexes are similar in appearance, males are slightly larger.
Immature birds are a paler yellow splotched with brown.
I'iwis can produce a wide variety of sounds from strange metallic squeaks to clear flute-like calls. The 'I'iwi is a member of the Drepanidinae, the Hawaiian Honeycreepers, a group found only in the Hawaiian islands. They were once found on all of six largest forested islands in the Hawaiian chain but are disappearing rapidly on the lower elevation islands of Molokai and O'ahu. Extensive surveys on O'ahu from 1994 to 1996 located only eight individuals. They have been extinct on Lanai since 1929.