A myriad of colorful native forest birds called honeycreepers are found in Hawaii’s stunning Haleakalā National Park — and exist nowhere else on earth.
They are a key part of the ecosystem, pollinating Hawaii’s native plants, eating insects, and supporting the forests — which filter the rainfall that provides drinking water to countless communities.
But the honeycreepers are in trouble.
Between human impacts to their natural environment and the infiltration of non-native mosquitoes spreading avian malaria, populations of birds are on the brink.
Historically, more than 50 species of honeycreepers lived on the Hawaiian Islands, but today, only 17 species remain, with Haleakalā National Park home to six of the remaining forest bird species.
While many of the birds have sought safety in cooler elevations, where the mosquitoes can’t reach them, warming temperatures have made this refuge less reliable.
To keep these remaining populations from going extinct, immediate action must be taken.
Last fall, the National Parks Service and the Pacific Island Network began a $13.2 million program to protect the birds from avian malaria, partnering with the state of Hawaii and nonprofits like the Maui Forest Bird Recovery Project.
And it involves releasing hundreds of thousands of mosquitoes into the park.
The program employs the Wolbachia incompatible insect technique, which prevents mosquito reproduction. The technique relies on Wolbachia, a bacterium that lives naturally within most insects and prevents them from reproducing viable offspring with partners that have a different strain of Wolbachia.
Instead of genetically modifying the mosquitoes to be infertile, the insects are still able to breed, but — with partners who have different strains of Wolbachia — their eggs will not hatch.
This creates a safe method to reduce mosquito reproduction, therefore shrinking the mosquito population — and the threat of avian malaria.
“This effort therefore uses a natural process to try to protect forest birds without harming the environment, humans, or other animals,” an article from the NPS explained.
“Although similar mosquito control methods have been used worldwide to protect humans from mosquitoes and mosquito-borne diseases such as dengue, Zika, and chikungunya, this is a frontier for conservation in national parks.”
So, every week in Maui, a small helicopter is loaded with 250,000 to 500,000 male mosquitoes, who will mate with their wild female counterparts, who will go on to produce inviable eggs. (Mosquitoes only live a few weeks, so these releases are ongoing to continue reaching the most difficult-to-access populations).
According to the NPS, the “deliveries” of these mosquitoes are scheduled around twice a week, “using drones or helicopters to drop capsules that resemble large, biodegradable Keurig pods filled with thousands of male mosquitoes.”
To succeed, the program requires an aggressive level of technical and regulatory work, with an urgent timeline that has been in development for the past decade.
It’s also important to note that it has received opposition from some groups that argue the program could have other negative impacts on the environment, though a judge ruled in favor of the program earlier this year.
“We are in an ongoing extinction crisis,” Chris Warren, forest bird program coordinator at Haleakalā National Park in Maui, told NPR earlier this year. “The only thing more tragic than these things going extinct would be them going extinct and we didn't try to stop it.”
Indeed, the crisis has reached dire levels. According to the NPS, fewer than 200 kiwikiu remain in the wild, down from a population of roughly 500.
Not located within the park but still a vital part of the area’s ecosystem, Maui’s akikiki bird declined from 450 birds in 2018 to just five in 2023. And as of 2024, a single akikiki is known to be in the wild (though a small captive population was established a few years ago).
As soon as nine days after a bite from an infected female mosquito, these honeycreepers face a 95% mortality rate.
“That’s the pressure we’re feeling with this. Any delays are distressing. We are not jumping in too fast — we have done the requisite small-scale studies, and now the rubber is meeting the road,” Warren added in a statement for the NPS. “We are doing it, and then we’re learning how we’re going to do it better as we do it.”
Prior to introducing the IIT mosquito method, experts attempted to locate the key population centers for the most endangered forest birds to focus their conservation efforts there, protecting native forest habitat over decades.
But with the pervasive nature of mosquitoes killing birds at an alarming rate, the experts had to expand their efforts to something a little less traditional.
“We realized there was no longer any running from the mosquitoes,” Christa Seidl of the Maui Bird Recovery Project told NPR. “If we don’t do anything, we will lose many of our native species.”
Although the work is fickle, and the methods unconventional, a shred of hope — a melody of birdsong — remains. If this program works, it could lay the groundwork for similar efforts in Hawaii Volcanoes National Park and other critical habitats in the area.
“[It] provides a model for how the NPS can use innovative techniques to address a wide range of invasive species and human health concerns in parks,” a statement from the parks service said.
“As a result of this safe, targeted technique, the mosquito population will crash, giving our forest birds a fighting chance.”
Header images courtesy of NPS/David Yates
