Hawaii’s most iconic forest bird, the iiwi, will receive an added level of federal protection as the U.S. Fish and Wildlife Service announced Tuesday that it plans to designate more than 275,000 acres as critical habitat for the threatened honeycreeper.

The announcement to protect habitat on Kauai, Maui and the Big Island comes a year and a half after it was sued by the Center for Biological Diversity for failing to designate critical habitat.

Maxx Phillips, the center’s Hawaii director and staff attorney, said that while it shouldn’t have taken a lawsuit, the federal agency in the end made the right call.

“These birds are facing pretty intense pressures,” Phillips said. “Protecting the places they call home will help them have a fighting chance.”

The proposed rule is scheduled to be published today in the Federal Register. The federal agency will accept comments about the rule for the next 60 days and hold a Zoom online informational meeting Feb. 10 from 6 to 6:45 p.m., followed by a public hearing from 6:45 to 8 p.m.

The effort is the latest government action that aims to give Hawaii’s forest birds a greater chance of survival in the face of ongoing declines in population.

Two weeks ago the U.S. Department of Interior formally announced a plan to prevent the extinction of imperiled Hawaiian birds, part of a $14 million multiagency campaign to battle the disease-carrying mosquitoes that are the primary threat to Hawaii’s honeycreepers.

Iiwi — with their bright red plumage, black wings and long, curved bill — were considered one of the most common of the native forest birds in Hawaii by early naturalists, found from sea level to the tree line across all the major islands.

In the late 1800s, however, the iiwi began to disappear from low-elevation forests due to habitat loss and avian diseases, and by the mid-1900s the species was largely absent from sea level to mid-elevation forests.

Today iiwi are no longer found on Lanai and only a few might live on Oahu and Molokai and in West Maui. The remaining populations, like their honeycreeper cousins, are restricted to high-elevation forests above 4,000 feet on Hawaii island and Kauai and in East Maui.

These high-elevation areas generally have temperatures cool enough to retard the spread of avian malaria and avian pox, but climate change is allowing the disease-carrying mosquitoes to go even higher in the forest.

In 2017 the iiwi population was estimated at 600,000, with some 90% of them on the Big Island, 10% on Maui and less than 1% on Kauai.

Also in 2017 the Fish and Wildlife Service formally declared the iiwi a threatened species.

Under the Endangered Species Act, the service is required to designate critical habitat — the habitat needed to support recovery of the species — at the time of listing or “under limited circumstances, within one year.”

But the agency didn’t do that, prompting action by the Center for Biological Diversity.

Once critical habitat is designated, other federal agencies must consult with the Fish and Wildlife Service to ensure actions they fund, authorize or undertake are not likely to destroy or adversely modify the designated habitat.

Phillips said it has been shown that endangered species that do not have designated critical habitat are half as likely to avoid extinction.