The Smithsonian's National Museum of Natural History said the feathers are the only known plumage of the prehistorically extinct birds that once inhabited the Hawaiian Islands.
The feathers retained enough microscopic structure to allow the scientists to confirm the classification of the bird, Apteribis sp, as a close relative of the American white ibis and scarlet ibis.
The feathers also retained enough pigmentation for ornithologists Carla Dove and Storrs Olson to determine that the bird was brown-black to ivory-beige in color.
"This find is highly unusual because feathers do not preserve well and often decay before a bird is fossilized," Dove said Wednesday in a Smithsonian release. "These weren't fossil imprints in a rock, but feathers and bones we could actually pick up."
The findings were published in the September issue of the Journal of Paleontology.