The poo-uli (Melamprosops phaeosoma) or black-faced honeycreeper is an extinct species of passerine bird that was endemic to the island of Maui in Hawaiʻi. It is considered to be a member of the Hawaiian honeycreepers, and is the only member of its genus Melamprosops. It had a black head, brown upper parts and pale gray underparts. This bird inhabited only the wetter, easternmost side of Maui, where it had rapidly decreased in numbers. With extinction threatening, efforts were made to capture birds to enable them to breed in captivity. These efforts were unsuccessful; in 2004, only two known birds remained, and since then, no further birds have been sighted. A 2018 study recommended declaring the species extinct, citing bird population decline patterns and the lack of any confirmed sightings since 2004, and in 2019, the species was declared extinct.
The poo-uli was brown above and grayish-white below, with a broad black mask extending behind the eye. Adults were silvery-gray above the mask, shading into brown at the crown, with a bold, pale patch just behind the mask. Juveniles were similar but buffier below with a smaller mask and without gray above. Most published images of the poouli are of the juvenile plumage.
The poo-uli was discovered in 1973 when students from the University of Hawaiʻi found the bird on the north-eastern slopes of Haleakalā on the island of Maui. It was found during the Hana Rainforest Project at an altitude of above sea level. The poo-uli was the first species of Hawaiian honeycreeper to be discovered since 1923.
It was dissimilar to other Hawaiian birds; evidence based on DNA analysis supports it as being the most ancient of all the Hawaiian honeycreeper lineages to survive to recent times, its lineage having split off from the rest of the Hawaiian honeycreepers during the late Miocene, about 5.7-5.8 million years ago. The Hawaiian honeycreeper lineage itself only diverged from its common ancestor with Carpodacus around 7.