The poo-uli, 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 has a black head, brown upper parts and pale grey underparts. This bird inhabits only the drier, easternmost side of Maui, where it has rapidly decreased in numbers. With extinction threatening, efforts were made to capture birds to enable them to breed in captivity. This has been largely 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 2020, the species was declared extinct.
Description
The poo-uli is brown above and grayish-white below, with a broad black mask extending behind the eye. Adults are silvery-gray above the mask, shading into brown at the crown, with a bold, pale patch just behind the mask. Juveniles are similar but buffier below with a smaller mask and without gray above. Most published images of the poouli are of the juvenile plumage.
Discovery and taxonomy
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 is dissimilar to other Hawaiian birds. Evidence based on DNA suggests it belongs to an ancient lineage of Hawaiian honeycreepers. It appears to have outlived all its close relatives; that is, if it had any close relatives. No other bird – living or fossil – has a structure similar to it.
Behavior
Its diet consists mostly of snails, insects, and spiders and it nests in native ‘ōhi‘a lehua forests.
Status and conservation
In the past, according to fossil records, it seems that the bird lived on the dry half of the island of Maui, across southwestern slope of Haleakalā at altitudes of. When the species was first discovered, 100–200 poo-uli were estimated to exist. There were only 76 birds per km2. By 1981, there were only 15 birds per km2. By 1985, there were only 8 per km2. That meant that from 1975, when it was first discovered, to 1985, only ten years later, the population had dropped by over 90 percent. In the 1980s, the poo-uli disappeared from the easternmost part of its range and was only found in the western branch of the Hanawi Stream. To preserve the poo-uli and other endangered fauna and flora, the State of Hawaii established the Hanawi Natural Area Reserve. This connected several protected areas to make one larger protective area. 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. The land was fenced off and by June 1996 they began to clear out the pigs from the closed areas. Four years and 202 pigs later, the poo-uli pen was completely cleared of pigs. 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. Rats, cats, and goats were still being removed from the poo-uli pen.
By 1997, only three individuals were known to exist. These had home ranges within the Hanawi Natural Area Reserve and the adjacent Haleakala National Park. In 2002, one of these, a female, was captured and taken to a male's home range in an attempt to get them to breed. The female, however, had flown back to her own territory, which was away, by the next day. There was also a ten-day expedition in 2004. The goal of this was to capture all three birds and bring them to a bird conservation center on the island, in the hope they would produce offspring. On September 9, 2004, one of the remaining birds, a male, was captured and taken to the Maui Bird Conservation Center in Olinda, in an attempt to breed the bird in captivity. However, biologists could not find a mate for the male before it died on November 26, 2004. If the two remaining birds still survive, they are over 20 years of age, nearing the end of their life, and probably have not been fertile for years. It is uncertain whether they are a male and female, or both are of the same sex. Since 2004, extensive surveys have failed to locate these or other individuals of this species and it could be extinct, but remains listed as critically endangered by BirdLife International until additional surveys have confirmed its extinction beyond reasonable doubt. Tissue samples have been taken from the male captured in 2004 for possible future cloning. The dramatic population decline has been attributed to a number of factors, including habitat loss, mosquito-borne diseases, predation by pigs, rats, cats, and small Asian mongooses, and a decline in the native tree snails that the poouli relied on for food. In 2019, after continued habitat degradation, presence disease of and invasive species, and a long period with no sightings, the IUCN classified this bird as Extinct.
