Both the Federal government and State of Hawaiʻi have endangered species laws. The State law is Hawaiʻi Revised Statutes HRS 195D) and is here: https://www.capitol.Hawaii.gov/hrscurrent/Vol03_Ch0121-0200D/HRS0195D/HRS_0195D-0004.htm. It automatically includes all the species that are listed under the Federal Endangered Species Act (ESA) and also includes the pueo and white tern on Oahu that are not listed under the Federal ESA. Media reporting on endangered species in Hawaiʻi often only mentions the Federal listing. These are unfortunate oversights as the State listing is a very important consideration, and critically so for plant species, which are not covered by the Federal ESA on private lands unless there is a federal nexus. The state has exercised a limited role in endangered species protection and management.
Under HRS 195D the state, along with the Federal government, oversees projects that cannot avoid impacts to threatened or endangered species through issuing an Incidental Take License and oversight of an associated Habitat Conservation Plan to minimize and mitigate impacts. There exists under HRS 195D an Endangered Species Recovery Committee (ESRC) that has specific authority to conduct oversight. The webpage for the ESRC is here: https://dlnr.hawaii.gov/wildlife/esrc/.
The Federal listing for Hawaiʻi can be found here: https://ecos.fws.gov/ecp/report/species-listings-by-state?stateAbbrev=HI&stateName=Hawaii&statusCategory=Listed. Links for details on each individual species is also available on that webpage. A map showing the counties where found is included but if a list of species with counties is desired go here: https://defenders-cci.org/app/ESA_counties/. For other information on species under the Federal ESA check here: https://ecos.fws.gov/ecp/species-reports. The STATE LISTING of threatened and endangered species is outdated but does include the several species not listed by under the Federal ESA. That listing is here: https://dlnr.hawaii.gov/dofaw/files/2013/09/Chap124a-Ex.pdf.
A Preventing Plant Extinction in Hawaiʻi video is here: https://www.youtube.com/watch?v=ARKDQv5fFdo.
A Wikipedia page has a list and information on critically endangered fauna in Hawaiʻi: https://en.wikipedia.org/wiki/Category:Critically_endangered_fauna_of_Hawaii.
An example of two endangered seabirds and efforts to prevent their extinction is in an Audubon magazine article – One Scientist’s Valiant Mission to Save Two of Hawaiʻi’s Endangered Seabirds: https://www.audubon.org/magazine/summer-2018/one-scientists-valiant-mission-save-two-Hawaiis.
Many species do not get the protection they need. An analysis by the author of this website of the IUCN red list and the NatureServe database in April 2020 for Hawaiian species designated as endangered or critically endangered (IUCN red list), or imperiled or critically imperiled (NatureServe conservation status) revealed over 600 species in these categories that are not currently listed threatened or endangered under Federal or Hawaii state law.
An additional area of concern is the limited designation of critical habitat. As a specific example, the Center for Biological Diversity sued the USFWS for not designated critical habitat as required under the Endangered Species Act for 14 plant and invertebrate species on Hawaiʻi Island: https://www.westHawaiitoday.com/2019/10/29/Hawaii-news/lawsuit-filed-to-protect-habitat-for-14-Hawaii-island-species/?utm_term=EndangeredSpecies&emci=27bf405f-85ff-e911-828b-2818784d6d68&emdi=bf0e9668-8801-ea11-828b-2818784d6d68&ceid=255491.
The US Fish and Wildlife Service (FWS) uses 11 categories to characterize critical habitat “units” under the ESA: dry and wet cliff, alpine, subalpine, dry-mesic-wet lowland and montane, coastal. Ecosystem units are designated in various critical habitat decisions in the Federal Register (Oahu, Maui, and Kauai only); summary lists and maps of units for the islands can be found here: http://geoportal.Hawaii.gov/search?q=critical.