The poo-uli (''Melamprosops phaeosoma'') or Hawaiian black-faced honeycreeper is an extinct

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

passerine A passerine () is any bird of the order Passeriformes (; from Latin 'sparrow' and '-shaped') which includes more than half of all bird species. Sometimes known as perching birds, passerines generally have an anisodactyl arrangement of their ...

bird that was

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

to the island of

Maui Maui (; Hawaiian language, Hawaiian: ) is the second largest island in the Hawaiian archipelago, at 727.2 square miles (1,883 km2). It is the List of islands of the United States by area, 17th-largest in the United States. Maui is one of ...

in Hawaiʻi. It is considered to be a member of the

Hawaiian honeycreeper Hawaiian honeycreepers are a group of small birds endemic to Hawaii. They are members of the finch family Fringillidae, closely related to the rosefinches (''Carpodacus''), but many species have evolved features unlike those present in any othe ...

s, 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

, where it had rapidly decreased in numbers. With

extinction Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

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.

Description

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.

Discovery

The poo-uli was discovered in 1973 when students from the

University of Hawaiʻi The University of Hawaiʻi System is a public college and university system in Hawaii. The system confers associate, bachelor's, master's, and doctoral degrees through three universities, seven community colleges, an employment training center, ...

found the bird on the north-eastern slopes of

Haleakalā Haleakalā (; Hawaiian: ), or the East Maui Volcano, is a massive, active shield volcano that forms more than 75% of the Hawaiian Islands, Hawaiian Island of Maui. The western 25% of the island is formed by another volcano, Mauna Kahalawai, als ...

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.

Taxonomy

It was dissimilar to other Hawaiian birds; evidence based on

DNA Deoxyribonucleic acid (; DNA) is a polymer composed of two polynucleotide chains that coil around each other to form a double helix. The polymer carries genetic instructions for the development, functioning, growth and reproduction of al ...

analysis supports it as being the most ancient of all the

lineages to survive to recent times, its lineage having split off from the rest of the Hawaiian honeycreepers during the late

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

, about 5.7-5.8 million years ago. The Hawaiian honeycreeper lineage itself only diverged from its common ancestor with ''

Carpodacus The rosefinches are a genus, ''Carpodacus'', of passerine birds in the finch family Fringillidae. Most are called "rosefinches" and as the word implies, have various shades of red in their plumage. The common rosefinch is frequently called the " ...

'' around 7.2 million years ago; this would make the divergence of the po ouli chronologically closer to the initial divergence from the common ancestor with ''Carpodacus'' than to the divergence of most other Hawaiian honeycreeper lineages (aside from the one containing '' Oreomystis'' and ''

Paroreomyza ''Paroreomyza'' is a genus of Hawaiian honeycreeper in the subfamily Carduelinae of the family Fringillidae. These birds are endemic to Hawaii. Taxonomy ''Paroreomyza'', along with '' Oreomystis'' (although their alliance is disputed), is the ...

'', which diverged about a million years after ''Melamprosops'''s lineage), most of which diverged after the mid-

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58mya. Around the time the po ouli lineage originated, Ni'ihau and

Kauai Kauai (), anglicized as Kauai ( or ), is one of the main Hawaiian Islands. It has an area of 562.3 square miles (1,456.4 km2), making it the fourth-largest of the islands and the 21st-largest island in the United States. Kauai lies 73 m ...

were the only two large Hawaiian islands in existence (aside from the then-larger

Northwestern Hawaiian Islands The Northwestern Hawaiian Islands also known as the Leeward Hawaiian Islands, are a series of islands and atolls located northwest of Kauai and Niihau, Niihau in the Hawaiian Islands, Hawaiian island chain. Politically, these islands are part of ...

), indicating that the po'ouli's lineage must have evolved there and eventually spread to

Maui Nui Maui Nui is a modern Geology, geologists' name given to a prehistoric Hawaii, Hawaiian island and the corresponding modern Biogeography, biogeographic region. Maui Nui is composed of four modern islands: Maui, Molokai, Molokaʻi, Lanai, Lānaʻi, ...

at some point after it first arose in the early

Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

, with the recent po ouli evolving on and/or eventually becoming restricted to Maui.

Diet

Its diet consisted mostly of

snail A snail is a shelled gastropod. The name is most often applied to land snails, terrestrial molluscs, terrestrial pulmonate gastropod molluscs. However, the common name ''snail'' is also used for most of the members of the molluscan class Gas ...

insect Insects (from Latin ') are Hexapoda, hexapod invertebrates of the class (biology), class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (Insect morphology#Head, head, ...

s, and

spider Spiders (order (biology), order Araneae) are air-breathing arthropods that have eight limbs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude spider silk, silk. They are the largest order of arachnids and ran ...

s and it nested in native ‘ōhi‘a lehua (''

Metrosideros polymorpha ''Metrosideros polymorpha'', the ''ōhia lehua'',; is a species of flowering evergreen tree in the Myrtus, myrtle family, Myrtaceae, that is Endemism, endemic to the six largest Hawaiian Islands, islands of Hawaii, Hawaii. It is a member of the ...

'') forests. Po’ouli relied more on an insectivorous diet because the snails' diets required more foraging.

Status and conservation

In the past, at least according to

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...

records, it appears that the po’ouli inhabited the drier half of the island of

, across the southwestern slope of

, at altitudes of . 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. The relatively recent arrival of lethal,

mosquito Mosquitoes, the Culicidae, are a Family (biology), family of small Diptera, flies consisting of 3,600 species. The word ''mosquito'' (formed by ''Musca (fly), mosca'' and diminutive ''-ito'') is Spanish and Portuguese for ''little fly''. Mos ...

-transmitted avian malaria in Hawaii quickly wiped out the low-elevation birds, forcing a rapid relocation, en masse, to higher elevations and mountain rainforests; this move showed a likely avoidance of mosquitoes by the birds. 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. 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: 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 Maui County (), officially the County of Maui, is a county in the U.S. state of Hawaii. It consists of the islands of Maui, Lānai, Molokai (except for a portion of Molokai that comprises Kalawao County), Kahoolawe, and Molokini. The latter ...

, the

National Park Service The National Park Service (NPS) is an List of federal agencies in the United States, agency of the Federal government of the United States, United States federal government, within the US Department of the Interior. The service manages all List ...

The Nature Conservancy The Nature Conservancy (TNC) is a global environmental organization headquartered in Arlington, Virginia, United States. it works via affiliates or branches in 79 countries and territories, as well as across every state in the US. Founded in ...

, 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. Melamprosops

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 was to capture the three birds and bring them to a conservation center on the island, with the hopes that they would produce captive-bred offspring. On September 9, 2004, one of the remaining birds, a male, was captured and taken to the Maui Bird Conservation Center in

Olinda Olinda () is a historic city in Pernambuco, Brazil, in the Northeast Region, Brazil, Northeast Region. It is located on the country's northeastern Atlantic Ocean coast, in the Recife metropolitan area, Metropolitan Region of Recife, the state ca ...

, in an attempt to breed the bird in captivity. However, biologists could not find a mate for the male before it died, around two months later, on November 26, 2004. It is uncertain whether the other two birds that remained at the time were a male and female, or two of the same sex. Since 2004, extensive surveys failed to locate these or any other individual po’ouli, indicating a possible extinction. However, they remained listed as

critically endangered An IUCN Red List critically endangered (CR or sometimes CE) species is one that has been categorized by the International Union for Conservation of Nature as facing an extremely high risk of extinction in the wild. As of December 2023, of t ...

BirdLife International BirdLife International is a global partnership of non-governmental organizations that strives to conserve birds and their habitats. BirdLife International's priorities include preventing extinction of bird species, identifying and safeguarding i ...

(and thereby the

IUCN The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the status ...

) until additional surveys had confirmed extinction beyond a reasonable doubt. Tissue samples were taken from the male captured in 2004 for possible future cloning. The

San Diego Zoo The San Diego Zoo is a zoo in San Diego, California, United States, located in Balboa Park (San Diego), Balboa Park. It began with a collection of animals left over from the 1915 Panama–California Exposition that were brought together by its ...

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

retains potentially viable poouli genetic material at their research center, the

Frozen Zoo A frozen zoo is a storage facility in which genetic materials taken from animals (e.g. DNA, sperm, eggs, embryos and live tissue) are stored at very low temperatures (−196 °C) in tanks of liquid nitrogen. Material preserved in this way ca ...

. The po’ouli’s dramatic population decline has been attributed to a number of factors;

habitat In ecology, habitat refers to the array of resources, biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species' habitat can be seen as the physical manifestation of its ...

loss from human activities, mosquito-transmitted disease, native habitat degradation caused by introduced Indian axis deer, predation by feral

pig The pig (''Sus domesticus''), also called swine (: swine) or hog, is an omnivorous, domesticated, even-toed, hoofed mammal. It is named the domestic pig when distinguishing it from other members of the genus '' Sus''. Some authorities cons ...

rat Rats are various medium-sized, long-tailed rodents. Species of rats are found throughout the order Rodentia, but stereotypical rats are found in the genus ''Rattus''. Other rat genera include '' Neotoma'' (pack rats), '' Bandicota'' (bandicoo ...

cat The cat (''Felis catus''), also referred to as the domestic cat or house cat, is a small domesticated carnivorous mammal. It is the only domesticated species of the family Felidae. Advances in archaeology and genetics have shown that the ...

s, and especially the small Asian mongoose have all contributed. An overall decline in the native tree snails (due to many of the same factors) that the poouli relied on for food has also been a leading cause in their disappearance. 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 Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

. On September 29, 2021, the U.S. Fish and Wildlife Service declared the Poʻouli extinct and the species was delisted from the

Endangered Species Act The Endangered Species Act of 1973 (ESA; 16 U.S.C. § 1531 et seq.) is the primary law in the United States for protecting and conserving imperiled species. Designed to protect critically imperiled species from extinction as a "consequence of e ...

on October 16, 2023.

Footnotes

References

* * * * * * * * * * * * * * *

External links

Species factsheet
– BirdLife International

BBC story
https://www.theguardian.com/environment/2022/may/04/extinction-obituary-hawaiian-poouli-bird-aoe Attempts to save the Poʻouli, The Guardian 4 May 2022.] {{Authority control Carduelinae Hawaiian honeycreepers Biota of Oahu Extinct birds of Hawaii Birds described in 1974 Taxa named by Tonnie Casey Taxa named by James Jacobi