The poʻo-uli (Melamprosops phaeosoma) [3] or Hawaiian black-faced honeycreeper is an extinct species of passerine bird that was endemic to the island of Maui in Hawaiʻi.

Around the time the poʻouli lineage originated, Ni'ihau and Kauai were the only two large Hawaiian islands in existence (aside from the then-larger Northwestern Hawaiian Islands), indicating that the po'ouli's lineage must have evolved there and eventually spread to Maui Nui at some point after it first arose in the early Pleistocene, with the recent poʻouli evolving on and/or eventually becoming restricted to Maui.

In the past, at least according to fossil records, it appears that the po’ouli inhabited the drier half of the island of Maui, across the southwestern slope of Haleakalā, at altitudes of 275–1,350 metres (902–4,429 ft).

Fossils show that the po'ouli once lived at Maui’s lower elevations in more arid environments, thriving on a presumed diet of native tree snails, invertebrates, insects and their larvae.

Moving to higher elevations also meant adjusting their diets, coming to avoid flying insects and focus on mollusks and other invertebrates.

Overall, the sharp decrease in numbers (and subsequent relocation of survivors) negatively affected the po’ouli’s once-thriving existence, their genetic diversity and population growth, reproduction and overall distribution.

This protection effort was only possible due to the work of several groups: the government, Maui County, the National Park Service, The Nature Conservancy, and several private companies.

As more pigs were removed from the other two pens, the population of native species that lived there, e.g. the Maui parrotbill and ʻākohekohe, rose slightly faster than they otherwise would have.

However, they remained listed as critically endangered by BirdLife International (and thereby the IUCN) until additional surveys had confirmed extinction beyond a reasonable doubt.

[8] The po’ouli’s dramatic population decline has been attributed to a number of factors; habitat loss from human activities, mosquito-transmitted disease, native habitat degradation caused by introduced Indian axis deer, predation by feral pigs, rats, cats, and especially the small Asian mongoose have all contributed.

In 2019, after continued habitat degradation, presence of disease and invasive species, and a long period with no sightings, the IUCN classified the po’ouli as extinct.