One of the most wondrous aspects of Hawaiʻi’s birds is the incredible radiation of species. See this page for more information on the amazing evolution of birds and other species in Hawaiʻi.
Below is an illustration from a course lesson given at the University of Washington: https://images.slideplayer.com/16/4932450/slides/slide_9.jpg.

A list and descriptions of species that embody the various forms of Hawaiian species, both surviving forms and those extinct is here: https://en.wikipedia.org/wiki/List_of_adaptive_radiated_Hawaiian_honeycreepers_by_form#Parrot-like_2.
DLNR 2015 SWAP individual factsheets for 33 forest bird species are here: https://dlnr.hawaii.gov/wildlife/hswap/fact-sheets/#ForestBirds-1. Links for each factsheet (with image or artists depictions) are here:
- O‘ahu ‘elepaio State and Federal Endangered
- Kaua‘i ‘elepaio
- Hawai‘i ‘elepaio
- Hawai‘i ‘amakihi
- Kaua‘i ‘amakihi
- O‘ahu ‘amakihi
- Anianiau (lesser ‘amakihi)
- Akekee (Kaua‘i ‘akepa) State and Federal Endangered
- Hawai’i ‘akepa State and Federal Endangered
- Maui ‘akepa State and Federal Endangered
- ‘Oma‘o (Hawai‘i thrush)
- Puaiohi (small Kaua‘i thrush) State and Federal Endangered
- Kama‘o (large Kaua‘i thrush) State and Federal Endangered
- Oloma‘o (Moloka‘i thrush) State and Federal Endangered
- ‘Akikiki (Kaua‘i creeper) State and Federal Endangered
- Hawai‘i creeper State and Federal Endangered
- Maui ‘alauahio (Maui creeper)
- ‘Alauahio (O‘ahu creeper) State and Federal Endangered
- Kakawahie (Moloka‘i creeper) State and Federal Endangered
- Kaua‘i nuku pu‘u State and Federal Endangered
- Maui nuku pu‘u State and Federal Endangered
- Kaua’i ‘o‘o State and Federal Endangered
- Bishop’s ‘o‘o
- ‘Akiapola‘au State and Federal Endangered
- Po‘ouli State and Federal Endangered
- ‘Apapane
- ‘I‘iwi State and Federal Threatened, State Endangered on specific Islands
- Palila State and Federal Endangered
- Maui parrotbill State and Federal Endangered
- ‘Akohekohe (crested honeycreeper) State and Federal Endangered
- ‘O‘u State and Federal Endangered
- Kaua‘i ‘akialoa State and Federal Endangered
- ‘Alala (Hawaiian crow) State and Federal Endangered
A nice summary for Iiwi is here: https://abcbirds.org/bird/iiwi/?omcampaign=membership?hook&eType=EmailBlastContent&eId=0d5a9ae8-c306-4616-8f77-e8c7237848b8.
A Consensus Taxonomy for the Hawaiian Honeycreepers, D. Pratt 2014: https://sites01.lsu.edu/wp/mnspapers/files/2014/10/85.pdf
Individual Wikipedia page links for endemic forest birds of Hawaiʻi broken down by family are here: https://en.wikipedia.org/wiki/List_of_endemic_birds_of_Hawaii. Bold text indicates IUCN designations (VU-vulnerable, EN-Endangered, CR-critically endangered, EX-Extinct, EW-extinct in the wild; LC indicates least concern).
Mohoidae (Nectarivorous songbirds within its own unique family)
- Kauaʻi ʻōʻō, Moho braccatus † EX
- Oʻahu ʻōʻō, Moho apicalis † EX
- Bishop’s ʻōʻō, Moho bishopi † EX
- Hawaiʻi ʻōʻō, Moho nobilis † EX
- Kioea, Chaetoptila angustipluma † EX
Corvidae (Crows)
- Hawaiian crow or ʻalala, Corvus Hawaiiensis EW
Monarchidae (Monarch flycatchers)
- Kauaʻi ʻelepaio, Chasiempis sclateri VU
- Oʻahu ʻelepaio, Chasiempis ibidis EN
- Hawaiʻi ʻelepaio, Chasiempis sandwichensis VU
Sylviidae (Passerine group)
- Laysan millerbird, Acrocephalus familaris familaris † (A. familiaris: CR)
- Nihoa millerbird, Acrocephalus familaris kingi (A. familiaris: CR)
Turdidae (Thrushes)
- Kamaʻo, Myadestes myadestinus † EX
- ʻĀmaui, Myadestes woahensis † EX
- Olomaʻo, Myadestes lanaiensis lanaiensis (M. lanaiensis: CR)
- ʻOmaʻo, Myadestes obscurus VU
- Puaiohi, Myadestes palmeri CR
Drepanididae (Hawaiian Honeycreepers)
- Laysan finch, Telespiza cantans VU
- Nihoa finch, Telespiza ultima CR
- ʻŌʻū, Psittirostra psittacea CR
- Lanaʻi hookbill, Dysmorodrepanis munroi † EX
- Palila, Loxioides bailleui CR
- Kauaʻi palila, Loxioides kikuichi † EX
- Lesser koa-finch, Rhodacanthis flaviceps † EX
- Greater koa-finch, Rhodacanthis palmeri † EX
- Kona grosbeak, Chloridops kona † EX
- Maui parrotbill, Pseudonestor xanthophrys CR
- Kauaʻi ʻakialoa Akialoa stejnegeri or Hemignathus (ellisianus) procerus † EX
- Oʻahu ʻakialoa, Akialoa ellisiana or Hemignathus ellisianus ellisianus † EX
- Maui Nui ʻakialoa, Akialoa lanaiensis or Hemignathus (ellisianus) lanaiensis † EX
- Lesser ʻakialoa, Akialoa obscura or Hemignathus obscurus † EX
- Common ʻamakihi, Hemignathus virens LC
- Oʻahu ʻamakihi, Hemignathus flavus VU
- Kauaʻi ʻamakihi, Hemignathus kauaiensis VU
- Greater ʻamakihi, Hemignathus sagittirostris † EX
- Maui nukupuʻu, Hemignathus affinis CR
- Kauai nukupuʻu, Hemignathus hanapepe CR
- Oʻahu nukupuʻu, Hemignathus lucidus † EX
- Giant nukupuʻu, Hemignathus vorpalis † EX
- ʻAkiapolaʻau, Hemignathus munroi EN
- ʻAnianiau, Magumma parva VU
- ʻAkikiki, Oreomystis bairdi CR
- Hawaiʻi creeper, Oreomystis mana EN
- Oʻahu ʻalauahio, Paroreomyza maculata CR
- Maui ʻalauahio, Paroreomyza montana EN [GM note: this is the only Hawaiʻi forest bird species listed as Endangered by the IUCN but is not listed under state or federal law]
- Lanaʻi ʻalauahio, Paroreomyza montana montana † EX
- Kakawahie, Paroreomyza flammea † EX
- ʻAkekeʻe, Loxops caeruleirostris CR
- Hawaiʻi ʻakepa, Loxops coccineus EN
- Maui ʻākepa, Loxops coccineus ochraceus † EX
- Oʻahu ʻākepa, Loxops coccineus wolstenholmei † EX
- ʻUla-ʻai-hawane, Ciridops anna † EX
- ʻIʻiwi, Vestiaria coccinea VU
- Hawaiʻi mamo, Drepanis pacifica † EX
- Black mamo, Drepanis funerea † EX
- ʻAkohekohe, Palmeria dolei CR
- ʻApapane, Himatione sanguinea LC
- Laysan honeycreeper, Himatione fraithii † EX
- Poʻouli, Melamprosops phaeosoma CR
An important resource (not available free but with some accessibility of text at https://www.google.com/books/edition/Conservation_Biology_of_Hawaiian_Forest/oqe9zJNESOsC?hl=en&gbpv=1&printsec=frontcover) is Conservation Biology of Hawaiian Forest Birds, Implications for Island Avifauna Edited by Thane K. Pratt, Carter T. Atkinson, Paul C. Banko, James D. Jacobi, and Bethany L. Woodworth.
Here are websites of two great conservation organizations: https://mauiforestbirds.org/; https://kauaiforestbirds.org/.
This link has beautiful artwork for the Hawaiian Honeycreepers: http://www.hdouglaspratt.com/Art_Gallery/theHawaiianhoneycreepers.html.
Videos, photos, and sound recordings of Hawaiian birds at the Internet Bird Collection (IBC) can be found here: https://www.hbw.com/ibc/species.
Alala Project
The Alala project was initiated to bring back the Hawaiian Crow, a species kept alive only in captivity up until recently. The unfolding story of how the species was prepared for release, and then released beginning in 2016, with some setbacks, is a fascinating story. Some of the details are here: https://dlnr.hawaii.gov/alalaproject. As of October 2020, news reports said that all releasted birds surviving were going to be recaptured.

As explained on the website Due to a sharp drop in their population, a few Alala were brought into captivity in the 1970s. As of 2017, there were over 125 birds in two breeding facilities managed by the Hawaiʻi Endangered Bird Conservation Program (San Diego Zoo Global). A recent story in Audubon magazine describes the success of the program: https://www.audubon.org/news/reintroduced-Hawaiian-crows-are-learning-how-live-wild.
Conservation Biology of Hawaiian Forest Birds: Implications for Island Avifauna. This book is available for purchase. A review is here: https://bioone.org/journals/the-condor/volume-112/issue-4/cond.2010.112.4.863/Conservation-Biology-of-Hawaiian-Forest-Birds–Implications-for-Island/10.1525/cond.2010.112.4.863.full
Forest Bird Videos:
Unique birds of Hawaiʻi: https://www.youtube.com/watch?v=LI0hgUePEIQ.
Jack Jeffrey video: https://www.youtube.com/watch?v=LI0hgUePEIQ&ebc=ANyPxKrCIDMQMb2FwgM6fsO9-wZgsDIx_WVlDabcx6BK8N_AxEGk3kkZ3pbWi1VRcmifzhvTA63UB7AmsiJ2o9r9_XNy0qOTkA&nohtml5=False.
Iiwi feeding: https://www.youtube.com/watch?v=nZyuqS-Kb7k.
Kauai forest bird preservation: https://www.youtube.com/watch?v=eM24DCwlpsI.
Akikiki: https://www.youtube.com/watch?v=L6ykVMuQhzo.
Native forest birds: https://www.youtube.com/watch?v=L6ykVMuQhzo.
Alala tool use: https://www.youtube.com/watch?v=ZOUyrtWeW4Q.