The U.S. Fish and Wildlife Service is delisting 21 species — including eight Hawaii bird species — from the Endangered Species Act due to extinction.

USFWS officials said Monday that based on rigorous reviews of the “best available science” for each species, it has determined they are extinct. Most were likely already extinct when listed in the 1970s and 1980s as endangered, they said.

The eight bird species, all forest honeycreepers, include the Kauai akialoa, Kauai nukupuu, Kauai oo, kamao or large Kauai thrush, Maui akepa, Maui nukupuu, Molokai creeper and poouli, also known as the black-faced honeycreeper.

“Federal protection came too late to reverse these species’ decline, and it’s a wake-up call on the importance of conserving imperiled species before it’s too late,” said service Director Martha Williams in a news release. “As we commemorate 50 years of the Endangered Species Act this year, we are reminded of the act’s purpose to be a safety net that stops the journey toward extinction. The ultimate goal is to recover these species, so they no longer need the act’s protection.”

The USFWS did not end up removing Phyllostegia glabra var. lanaiensis, a flowering plant from the mint family that was proposed for removal along with the birds in 2021, because it might still survive.

“Most of these extinct birds are Hawaiian species that were unique to those islands,” said Michael Parr, president of the American Bird Conservancy, in a statement. “It’s a tremendous loss. Their ESA listings happened too late for their protection and recovery. Sadly, this tragic outcome could have been prevented if actions to conserve their habitats had been taken sooner.”

He said it would be wrong to suggest the Endangered Species Act has failed because most of these species were already extinct or very rare and threatened when the act became law.

“The ESA’s success rate has actually been extremely good with very few extinctions and many species recoveries since it was passed,” he said.

But Hawaii, which was once a bird paradise, is now the bird extinction capital of the world, he said, with many more bird species on the brink due to habitat loss, invasives and non-native diseases transmitted by invasive mosquitoes.

The nonprofit Center for Biological Diversity said the loss highlights the need for more action to stop the extinction crisis, which already includes about 650 U.S. species.

“This is a heartbreaking reminder that we are in the midst of an extinction crisis, with our Hawaiian forest birds on the front line,” staff attorney Maxx Phillips, the center’s Hawaii director, said in an email. “As we mourn the loss of these eight irreplaceable birds it is important to remember that all of our last remaining Hawaiian honeycreepers are inexcusably sliding towards a similar fate.”

Scientists predict that Kauai’s akikiki and East Maui’s kiwikiu, or Maui parrotbill, will be extinct in the wild as early as 2024, she said.

Phillips said avian malaria transmitted by invasive mosquitoes is driving the extinction of Hawaii’s forest birds, which is further exacerbated by climate change. Warmer temperatures associated with climate change allow mosquitoes to expand their range into higher elevations in Hawaii, increasing the risks of avian malaria and avian pox.

The center supports the Incompatible Insect Technique, which disrupts the mosquitoes’ breeding cycle through the introduction of male mosquitoes containing a strain of Wolbachia bacteria. A coalition of state, federal, private and nonprofit partners including the American Bird Conservancy have launched a project to introduce the mosquitoes to Hawaii, starting with Maui and Kauai.

The technique has met with resistance from a group called Hawaii Unites, which filed a lawsuit attempting to temporarily block officials from releasing the mosquitoes on Maui, saying more study needs to be done due to unknown consequences.

On Friday the state Department of Land and Natural Resources said it was a step closer to launching the project on Kauai.

HAWAIIAN BIRDS TO BE DELISTED DUE TO EXTINCTION

>> Kauai akialoa, listed 1967, last confirmed sighting 1960s

>> Kauai nukupuu, listed 1970, last confirmed sighting 1899

>> Kauai oo, listed 1967, last confirmed sighting 1987

>> Large Kauai thrush, listed 1970, last confirmed sighting 1987

>> Maui akepa, listed 1970, last confirmed sighting 1988

>> Maui nukupuu, listed 1970, last confirmed sighting 1996

>> Molokai creeper, listed 1970, last confirmed sighting 1963

>> Poouli, listed 1975, last confirmed sighting 2004

Source: USFWS