The Hawai’i Oo (Moho nobilis) was an endemic passerine bird from the Hawaiian Islands, classified under the now-extinct Mohoidae family, also known as Hawaiian honeyeaters. It was once widespread on the Big Island of Hawaii, with records indicating its ability to inhabit a range of altitudes.
The species was last documented in 1934, making it one of several Hawaiian birds that became extinct following human exploitation and ecosystem degradation.

Profile
Common name | Hawai’i Oo |
Scientific name | Moho nobilis |
Order | Passeriformes |
Family | Mohoidae |
Genus | Moho |
Identification | Yellow feather tufts, rapid wing beats with buzzing sound |
Range | Hawaii (Big Island) |
Habitat | Montane and lowland forest canopies |
Diet | Nectar, bananas, insects, larvae |
Conservation status | Extinct (Last record in 1934) |
Discovery
The Hawai’i Oo was first described scientifically from specimens collected by naturalists during Captain James Cook’s third voyage (1779). These specimens were later analyzed in England and formally described by John Latham in A General Synopsis of Birds (1781–1785) as the yellow-tufted bee-eater. In 1786, Blasius Merrem established the genus Moho, placing this and other closely related species within a distinct taxonomic group.
The species belonged to Mohoidae, a family of Hawaiian endemic passerines initially classified with honeyeaters (Meliphagidae) due to their nectar-feeding adaptations. However, genetic studies later revealed that Mohoidae were unrelated to true honeyeaters and instead formed a distinct radiation within Passeriformes.
Identification
The Hawai’i Oo was a medium-sized songbird, measuring 30-32 cm (12-13 in) in total length, with a wing length of 11-11.5 cm (4.3-4.5 in) and a tail length of up to 19 cm (7.5 in). It had dark plumage with distinctive yellow tufts on its lower abdomen and underwings. Its wings beat rapidly, producing a buzzing sound in flight. The bird’s call was a harsh, clear “o’o”, from which its name is derived. There were no clear records of sexual dimorphism, and the appearance of juveniles was never fully documented.
Range and habitat
The Hawai’i Oo was endemic to the Big Island of Hawai’i, where it was historically widespread across various elevations. It inhabited montane and lowland forests, primarily in the upper canopy of native trees such as Ohi’a (Metrosideros polymorpha) and Olapa (various species of Cheirodendron). These forests provided essential resources, including nectar-producing flowers and suitable cover.

Behaviour
The Hawai’i Oo primarily occupied the upper canopy of forests, though specific nesting behavior remains largely unknown. Despite extensive searches, no nests or eggs were ever documented, but field observations by Robert Cyril Layton Perkins recorded recently fledged juveniles, confirming that successful breeding did occur.
Like other Moho species, it likely played a role in pollination, feeding primarily on nectar while also consuming insects and small fruits. It was an active bird, moving swiftly through the treetops in search of food.
Diet
The Hawai’i Oo was a nectar eater, primarily feeding on the flowers of native Hawaiian trees, including ‘Ohi’a lehua (Metrosideros polymorpha). It also consumed small fruits, insects, and larvae, making it an opportunistic forager. Its feeding habits played a key role in pollination and seed dispersal, contributing to the health of Hawaiian forest ecosystems.
Culture
The Hawai’i Oo was closely associated with Hawaiian royalty, valued for its yellow feathers, which were woven into ceremonial cloaks, helmets, and capes. Traditional practices dictated that captured birds be released after feather collection, though it is unclear how often this was followed.

Historical accounts suggest that some birds died from the stress of handling, while others were reportedly consumed, with sources mentioning their preparation in fat-based cooking.
Threats and conservation
The decline of the Hawai’i Oo was a gradual process driven by multiple factors. Continuous trapping for feathers significantly reduced population numbers, as the species was heavily exploited for its role in Hawaiian royal garments.
Large-scale deforestation further impacted its survival, altering the composition of native forests and reducing the availability of essential resources. The introduction of non-native birds brought new threats, including avian malaria and pox, both of which were particularly devastating to Hawaiian avifauna.
Additionally, the arrival of invasive plant species and ungulates contributed to the collapse of the island’s ecosystem, further disrupting the species’ habitat and food sources.
The last confirmed record of the Hawai’i Oo dates to 1934, when a single individual was heard singing on Mauna Loa. No verified sightings occurred after this date.
Similar species
The Hawai‘i Oo was part of the now-extinct Mohoidae family, commonly referred to as Hawaiian honeyeaters. While no living relatives remain, it shared characteristics with several other Moho species that once inhabited the Hawaiian Islands.
Bishop’s Oo (Moho bishopi)
Slightly smaller than Hawai’i Oo, Bishop’s Oo was found on Moloka’i and had similar yellow underwing tufts. Its range was more restricted, and it disappeared earlier than Moho nobilis.
O’ahu Oo (Moho apicalis)
This species had more contrasting plumage compared to Moho nobilis, with a distinct vocalization. It was endemic to O’ahu and was one of the earlier Moho species to go extinct, disappearing by the mid-19th century.
Kaua’i Oo (Moho braccatus)
The last surviving member of Mohoidae, the Kaua’i Oo persisted into the late 20th century, with the final confirmed recording made in 1987. Its call was one of the last vocal traces of this unique bird family.
Ecological comparisons
Although Moho species were historically grouped with honeyeaters (Meliphagidae), genetic research revealed that they evolved nectar-feeding traits independently. Some surviving Hawaiian honeycreepers (Drepanidinae), such as the Iiwi (Drepanis coccinea), exhibit similar feeding behaviors and ecological roles, making them the closest functional analogs to the extinct Moho lineage.
Further reading
The extinction of Moho nobilis is part of a larger decline in Hawaiian avifauna, driven by habitat loss, hunting, and invasive species. Its disappearance underscores the fragility of island ecosystems and the lasting impact of human activity on specialized species.
For more on Moho and Hawaiian bird conservation, explore the resources below.
- Perkins, R.C.L. (1903). Fauna Hawaiiensis: Vertebrata (Aves, Reptilia, Amphibia, Pisces). Cambridge University Press.
- Latham, J. (1781–1785). A General Synopsis of Birds.
- Olson, S.L., & James, H.F. (1982). Prodromus of the fossil avifauna of the Hawaiian Islands. Smithsonian Institution Press.
- Olson, S.L., & James, H.F. (1994) (Volume 15, pages 91–102). “A Chronology of Ornithological Exploration in the Hawaiian Islands from Cook to Perkins.” Studies in Avian Biology.
- Pratt, H.D. (2005). The Hawaiian Honeycreepers: Drepanidinae. Oxford University Press.
- Hume, J.P. (2017). Extinct Birds. Bloomsbury Publishing.