HONOLULU— The Center for Biological Diversity today sued the U.S. Fish and Wildlife Service for failing to designate critical habitat and develop a recovery plan for the threatened ‘i‘iwi, the best known of Hawai‘i’s imperiled honeycreepers.
‘I‘iwi are medium-sized Hawaiian forest birds known for their iconic bright red plumage, black wings and distinctive long, curved bill. Because of the extensive threats of mosquito-borne diseases, rapid ‘ōhi‘a death — an invasive fungal disease that is killing ‘ōhi‘a trees at an alarming rate — and climate change, the Service listed the ‘i‘iwi as threatened on Sept. 20, 2017.
The Endangered Species Act required the agency to designate critical habitat with its listing determination and develop a recovery plan for the bird. Yet the Service has failed to do so.
“The beautiful ‘i‘iwi needs our help and it needs it now,” said Maxx Phillips, the Center’s Hawai‘i director and staff attorney. “The U.S. Fish and Wildlife Service’s foot-dragging is unacceptable. Without the protections provided by critical habitat and a valid recovery plan, ‘i‘iwi will continue down a heartbreaking path towards extinction.”
The ‘i‘iwi was once one of the most abundant native forest birds across Hawai‘i. Unfortunately, it now persists on only three islands, with the population on Kaua‘i likely to go extinct within 30 years.
Like many native Hawaiian forest birds, ‘i‘iwi have an extremely low resistance to avian malaria, with an average 95% mortality rate. The combination of low resistance and high mortality means that nearly every ‘i‘iwi that comes into contact with avian malaria dies from the disease.
Since mosquitoes can’t live at higher elevations because of cooler temperatures, ‘i‘iwi have survived in higher-elevation forests. But as the impacts of global climate change continue to accelerate, temperatures at higher elevations in Hawai‘i are increasing at an unforeseen rate. This warming allows mosquitoes to expand their range into higher elevations, bringing with them avian malaria and avian pox. Additionally, the virus that causes avian malaria survives better in warmer temperatures, meaning warmer high elevation habitats will no longer be safe refuges from the disease.
“The future looks grim for ‘i‘iwi if we don’t act now,” Phillips said. “These rare birds deserve protected habitat and a valid plan to guide their recovery and prevent them from vanishing forever. In particular, we have to restore forests at higher elevations on the Big Island to give ‘i‘iwi space to move uphill and do whatever we can to control mosquitoes on all the islands.”
Today’s lawsuit was filed in U.S. District Court for the District of Hawaii.
Listing the ‘i‘iwi as threatened in 2017 was just the first step in ensuring its survival and recovery. Species without designated critical habitat are half as likely to move toward recovery as species with critical habitat. Without protections for its critical habitat, the ‘i‘iwi will continue to lose what little disease-free forest habitat remains. Additionally, species with timely recovery plans for two or more years are far more likely to improve than those without.
Alongside the devastating impacts of mosquitoes and climate change, rapid ‘ōhi‘a death is further threatening the ‘i‘iwi’s survival. ‘I‘iwi depend on the ‘ōhi‘a for nesting and foraging, surviving primarily on the nectar from lehua blossoms. Though originally limited to the island of Hawai‘i, as of June 2020, rapid ‘ōhi‘a death has spread to Kaua‘i, Maui and O‘ahu. Since there is no effective means of containing the disease, ‘ōhi‘a forest death poses a significant risk to the continued survival of the ‘i‘iwi.
Hawaiian forest birds, one of the most imperiled groups of birds in the world, are in crisis. Some 68% of Hawai‘i’s known endemic bird species have already gone extinct because of habitat loss, disease and invasive predators. Of the remaining 37 surviving endemic species, 33 are currently listed under the Endangered Species Act, although nine of these have not been observed recently and are thought by scientists to be extinct. Introduced mosquitoes and the diseases they carry are primary causes of the loss of all these birds.