Hawaii’s iconic iiwi, a honeycreeper bird known for its bright-red plumage, could go extinct in the coming decades without a designated, critical habitat for its numbers to recover.

On Tuesday, the Center for Biological Diversity filed its intent to sue the U.S. Fish and Wildlife Service for failing to designate that habitat.

The iiwi used to be one of the most abundant forest birds in Hawaii, according the nonprofit conservation group’s filing with federal officials Tuesday. Now, it’s found on just three islands and threatened to go extinct by 2050, the filing stated.

In fact, the iiwi is among the 17 remaining forest bird species poised for extinction in the islands if no action is taken to help their numbers recover. One of the main culprits in their demise are invasive, disease carrying mosquitos introduced to Hawaii. Avian malaria has decimated Hawaii’s honeycreepers and other forest bird populations.

The iiwi and similar species have gradually sought refuge at higher, cooler elevations where the mosquitos can’t reach them. But researchers say that climate change is warming those habitats and allowing the disease-carrying mosquitos to reach the birds.

The center’s filing also points to the gradual demise of Hawaii’s native Ohia trees. Iiwi survive primarily on the nectar of the lehua blossoms of those trees. However, at least one million Ohia have perished in recent years, mostly on Hawaii island, due to the spread of Rapid Ohia Death.

Federal officials have a legal duty to designate habitat and implement a recovery plan for the iiwi because it’s listed as an endangered species, the group’s filing states. The center says it intends to sue if the fish and wildlife service fails to correct that within 60 days.

“Time is running out for our iiwi,” Maxx Phillips, the Center for Biological Diversity’s Hawaii director and staff attorney, said in a statement Tuesday.