Extinction of species/taxa is a tragic and ongoing phenomenon in Hawaiʻi. Wikipedia has a page on extinction on Hawaiʻi: https://en.wikipedia.org/wiki/List_of_extinct_animals_of_the_Hawaiian_Islands. Here are the tallies from their categories:
Pre-European extinctions (before 1778) – 19 species of birds
Post-European extinctions – 27 species of birds
Possibly extinct birds – 5 species of birds
Insects – 69 species
Mollusks – 72 land snail species
Below is a tally from the Bishop Museum that was last revised in 2008: http://hbs.bishopmuseum.org/endangered/extinct.html. The page does include this note: “we will never know all of the species that have gone extinct in Hawaiʻi’s recent history”.
Birds – 28 species
Snails – 72 taxa
Plants – 97 taxa
For information on the pre-European extinctions see this article: Prehistoric Extinctions and Ecological Changes on Oceanic Islands, H. James (1995): https://www.researchgate.net/publication/242013255_Prehistoric_Extinctions_and_Ecological_Changes_on_Oceanic_Islands.
There is an excellent book with the title Extinct Birds of Hawaiʻi (2016) by Michael Walther and illustrated magnificently by Julian Hume. The information is based on fossil studies. The cover is shown below. The book lists 35 historical bird extinctions, 42 extinctions documented through subfossils. As shown in a comparison table in the book, the next highest total for anywhere in the world is New Zealand at a total of 50 species.
Others have slightly different numbers. The Wikipedia page at https://en.wikipedia.org/wiki/List_of_birds_of_Hawaii states the following: “Thirty-three of the 64 endemic species are extinct and two formerly established introduced species were extirpated.” A. Ziegler in his 2002 book Hawaiian Natural History, Ecology, and Evolution notes a total of 46 taxa of birds that are prehistorically extinct in the islands.
The photo below is part of a mural with the artists depictions of Hawai‘i birds before discovery, most now extinct, by Julian Hume at the Smithsonian in Washington DC.
The Center for Biological Diversity published lists of extinct species: Extinction and the Endangered Species Act, Suckling et al (2004). The lists for Hawaiʻi only were extracted by Andrew Esposito and they are here: http://www.birdwriter.com/Hawaii-the-isles-of-extinction/. Here are those lists.
Bishop’s ‘O ‘o Moho bishopi 1986
Kaua’i ‘O’o Moho braccatus 1987
Large Kaua’i Thrush Myadestes myadestinus 1989
Maui ‘Akepa Loxops coccineus ochraceus 1988
Moloka’i Thrush Myadestes lanaiensis rutha 1980
‘O ‘u Psittirostra psittacea 1989
Oahu ‘Akepa Loxops coccinea wolstenholmii 1976
Oahu alauahio Paroreomyza maculata 1990
Poo’uli Melamprosops phaeosoma 2004 *
‘alala – Hawaiian Crow Corvus Hawaiiensis 2003 (Extinct in Wild) *
Kaua`i `Akialoa Hemignathus ellisianus procerus 1965 *
Kakawahie Paroreomyza flammea 1963 *
* Additional to original 2004 list
Giffard’s ‘Ohe hedyleptan moth Omiodes giffardi 1982
O’ahu hesperomannia philodoria moth Philodoria sp. 1987
Meyrick’s banana hedyleptan moth Omiodes meyricki 1982
[An older Lepidopteran paper (with a list of some extinct) is here: CONSERVATIONSTATUS, No Date (part of a book?), W. Gagne (https://scholarspace.manoa.hawaii.edu/bitstream/handle/10125/18435/fourth-63-72.pdf?sequence=1).]
Nalo hihiu Drosophila substenoptera 1991
Nalo huluhulu Drosophila tarphytrichia 1975
Nalo kihikihi Drosophila heteroneura 1993
Nalo makamae Drosophila ochrobasis 1986
Nalo maka’ula Drosophila differens 1986
Nalo mea hula Drosophila neoclavisetae 1975
Nalo miki Drosophila hemipeza 1983
Koa nalo Drosophila musaphilia 1988
Digressa picture-wing Drosophila digressa 1986
Hawaiian picture wing Drosophila alsophila 1985
Hawaiian picture wing Drosophila toxochaeta 1985
Hawaiian picture wing Drosophila psilotarsalis 1985
Opuhe nalo Drosophila Aglaia 1980
Lysimachia venosa Lysimachia venosa 1990
Blood tetramolopium Tetramolopium consanguineum var. kauense 1980
Cyanea dolichopoda Cyanea dolichopoda 1992
Haha Cyanea truncate 1983
Scaevola hobdyi Scaevola hobdyi 1980
Cyanea habenata Cyanea habenata 1978
Oha, haha,Ohawai Cyanea eleeleensis 1977
Neal’s melicope Melicope nealiae 1979
Lanai phyllostegia Phyllostegia imminuta 1979
Hedyotis degeneri var. coprosmifolia Hedyotis degeneri var. coprosmifolia 1985
Hibiscadelphus crucibracteatus Hibiscadelphus crucibracteatus 1985
Four-angled pelea Melicope quadrangularis 1991
Haleakala stenogyne Stenogyne haliakalae 1984
Oahu tree snail bellula Achatinella bellula 1981
Achatinellid land snail Partulina kaaeana 1981
Achatinellid land snail Newcombia plicata 1989
Achatinellid land snail Newcombia cinnamomea 1975
Oahu tree snail bulimoides Achatinella bulimoides 1985
Oahu tree snail curta Achatinella curta 1989
Oahu tree snail leucorraphe Achatinella leucorraphe 1989
Oahu tree snail lorata Achatinella lorata 1974
Pupillid land snail (Mirapupa) Lyropupa perlonga 1980
Oahu tree snail phaeozona Achatinella phaeozona 1974
Oahu tree snail pupukanioe Achatinella pupukanioe 1980
Oahu tree snail swiftii Achatinella swiftii 1976
Oahu tree snail taeniolata Achatinella taeniolata 1978
Oahu tree snail turgida Achatinella turgida 1974
Oahu tree snail viridans Achatinella viridans 1979
Additional Information for Plants
An estimate from K. Wood et al. in PhytoKeys 69: 51–64 (2016) at https://phytokeys.pensoft.net/articles.php?id=8844 states that “Of the estimated 1191 native vascular plant species in Hawai‘i, 130 taxa are now presumed extinct. Evidently 41 of these possible extinctions have occurred in the Hawaiian lobeliads (Campanulaceae), a family renowned for their co-evolution with Hawai‘i’s unique forest birds”.
In 2019 K. Wood et al. authored Technical Report #314, a publication of The National Tropical Botanical Garden, A checklist of endemic Hawaiian vascular plant taxa that are considered possibly extinct in the wild: https://www.researchgate.net/publication/332916448_A_checklist_of_endemic_Hawaiian_vascular_plant_taxa_that_are_considered_possibly_extinct_in_the_wild.
The IUCN 2016 list of Hawai‘i plants recorded 38 species as Extinct and 87% of 415 species assessed threatened with extinction (categories: Critically Endangered, Endangered and Vulnerable): https://www.civilbeat.org/2016/09/iucn-extinction-threatens-87-percent-of-Hawaiis-native-plants/.
Additional Information for Birds
A gallery of paintings of extinct birds is shown below and obtained from the following website: https://news.mongabay.com/2011/11/aloha-and-welcome-to-the-planets-extinction-capital/.
A brief article with public domain images of some extinct Hawaiʻi birds is here: https://www.lostspeciesday.org/?p=776.
Documentation of loss and calls for conservation efforts for Hawaiian birds has been ongoing for many years. Here is an example from 1972: https://sora.unm.edu/sites/default/files/journals/wilson/v084n02/p0212-p0222.pdf. Yet, unfortunately, the loss continues to this day. According to a Helen James talk at the 2018 Pacific Seabird conference there were 107 species of land birds historically and only 11 of those are not now gone or endangered versus 34 in 2004.
A Hawaiian bird extinction crisis video is here: https://vimeo.com/42592260.
Additional Information for Land Snails
The situation with land snails is as bad or worse than for birds. Extinction was already documented many years ago in one subfamily of Hawaiʻi tree snails: Extinction in Hawaiian Achatinelline Snails by Michael G. Hadfield in the journal Malacologia (1986) 27(1): 67-81.
The endemic family of land snails, Amastridae has been greatly affected as documented in the paper Extinction in a hyperdiverse endemic Hawaiian land snail family and implications for the underestimation of invertebrate extinction Regnier et al. Conservation Biology, Volume 29, Issue 6, pages 1715–1723, December 2015: https://conbio.onlinelibrary.wiley.com/doi/abs/10.1111/cobi.12565 (not available free). The paper states that of the 325 known Amastridae species, 43 were originally described as fossil or subfossil and were assumed to be extinct. Of the remaining 282, 88 were thought extinct, 15 extant, and remaining 179 species had insufficient evidence of extinction, although they concluded most are probably extinct.
The most recent published descriptions of the status of all Hawaiʻi land snails are by two Bishop Museum scientists at: http://molluscanmusings.blogspot.com. In four separate articles they describe the status of the families below. Truly shocking and troubling results that deserve more attention. Note that a stated “Conservation Status” of Threatened or Endangered in the descriptions does not refer to an official listing under Federal or State law. Sadly, very few of these species (primarily the Achatinella tree snails) are officially listed under the laws, although further listings are certainly warranted.
Part 1 (March 2015) – describes basic information on the families of mollusks.
Part 2 (June 2015) summary:
Subfamilies: Amastrinae and Leptachatininae
Number of recognized species: 325
Number of species found in recent surveys: 14
Historical distribution: Kauai, Oahu, Maui, Lanai, Molokai, Hawaiʻi, Niihau, Kahoolawe, Northwest Hawaiian Islands (NWHI)
Current distribution: Kauai, Oahu, Maui
Conservation status: Endangered
Part 3 (October 2015) summary:
Subfamilies: Nesopupinae, Pupillinae, Vertigininae
Number of recognized species: 56
Number of species found in recent surveys: 23 (10 of unknown origins)
Historical distribution: Kauai, Oahu, Maui, Lanai, Molokai, Hawaiʻi, Niihau, Kahoolawe
Current distribution: Kauai, Oahu, Maui, Molokai, Lanai, Hawaiʻi
Conservation status: Threatened/Endangered
Part 4 (February 2016) summary:
An estimate from K. Wood et al. in PhytoKeys 69: 51–64 (2016). doi: 10.3897/phytokeys.69.8844 states that “Of the estimated 1191 native vascular plant species in Hawai‘i, 130 taxa are now presumed extinct. Evidently 41 of these possible extinctions have occurred in the Hawaiian lobeliads (Campanulaceae), a family renowned for their co-evolution with Hawai‘i’s unique forest birds”.
Number of recognized species: 1
Number of species found in recent surveys: 3 (2 undescribed)
Historical distribution: Oahu, Hawaiʻi
Current distribution: Kauai, Oahu, Maui, Molokai, Hawaiʻi
Conservation status: Threatened
Genus: Cookeconcha, Endodonta, Nesophila, Protoendodonta
Number of recognized species: 33
Number of species found in recent surveys: 3 (2 of which are undescribed)
Historical distribution: Kauai, Oahu, Maui, Lanai, Molokai, Hawaiʻi, Northwestern
Current distribution: Oahu, Nihoa
Conservation status: Threatened