Rising temperatures and mosquito-borne avian malaria have pushed one of Kauai's rarest native birds to the brink, raising fears that other forest birds could soon follow.
Deep in the mist-shrouded forests of Kauai's Alakai Wilderness, a small native bird once moved quietly through the branches, searching for insects among the mosses and lichens that cover the trees. Known as the akikiki, this unassuming forest bird existed nowhere else on Earth. For generations, the cool, wet mountain forests of Kauai provided a sanctuary for the species, far above the warmer lowlands where disease-carrying mosquitoes thrived. But that sanctuary has been disappearing.
Rising temperatures have allowed invasive mosquitoes to survive and reproduce at increasingly higher elevations, carrying a deadly parasite into forests that once offered protection. The resulting spread of avian malaria has devastated Kauai's native forest birds, and scientists now believe it has claimed the island's last wild akikiki.
The last-known individual, a bird nicknamed "Pakele," was observed on August 29, 2025. Despite continued conservation efforts, Pakele has not been seen since, leading researchers to conclude that the akikiki is now likely extinct in the wild. The disappearance marks a devastating milestone in Hawaii's ongoing struggle to protect its extraordinary native birdlife—and a warning that other species may be approaching the same fate.
A Deadly Disease Climbs the Mountains
For much of their evolutionary history, Hawaii's native forest birds lived in an environment largely free of mosquitoes and the diseases they carry. Isolated in the middle of the Pacific Ocean, these birds evolved without the defenses needed to withstand introduced pathogens such as avian malaria.
That vulnerability became increasingly dangerous after non-native mosquitoes and the malaria parasite arrived in the Hawaiian Islands. Avian malaria, caused by the parasite Plasmodium relictum, is transmitted through the bites of infected mosquitoes. The disease attacks birds' blood cells, causing anemia, weakness and potentially death. Many native Hawaiian forest birds are particularly susceptible, with infections often proving fatal.
Historically, cooler temperatures at higher elevations limited mosquito populations and slowed the development of the malaria parasite within them. These mountain forests became critical refuges for native birds retreating from disease-ridden lowlands.
Climate change is now eroding that natural protection.
As temperatures rise, mosquitoes can occupy higher elevations and the malaria parasite can develop in places that were once too cold for sustained transmission. The result is an expanding zone of disease exposure that reaches deep into the remaining strongholds of Hawaii's forest birds.
On Kauai, where the island's mountains are relatively low compared with those on Maui and Hawaii Island, the opportunities for birds to escape to cooler elevations are especially limited. For the akikiki, the consequences have been catastrophic.
The Collapse of a Species
New research published in the scientific journal Ornithological Applications provides compelling evidence that avian malaria played a central role in the akikiki's disappearance from the wild. The study, conducted by researchers Justin Hite, Lisa Crampton and Eben Paxton, examined years of monitoring data collected by the Kauai Forest Bird Recovery Project between 2015 and 2022.
Working in the remote Halepaakai region of the Alakai Wilderness Preserve, researchers tracked breeding pairs, nesting success and adult survival as the already fragile population continued to decline.
What they discovered was particularly troubling. Although nesting success remained relatively stable, the number of surviving adult birds fell sharply. The population was not simply failing to produce young. Instead, birds were disappearing faster than successful breeding could replace them. The pattern coincided with increasing evidence of avian malaria infections.
"Despite relatively stable nesting success, the population continued to collapse as avian malaria infections increased," said Justin Hite, formerly of the Kauai Forest Bird Recovery Project and now the Mosquito Control Project Coordinator with the Hawaii Department of Land and Natural Resources' Division of Forestry and Wildlife. "The findings indicate that increased mortality, rather than reproductive failure, drove the decline and provide compelling evidence of the devastating impact of mosquito-borne disease."
An Entire Forest Community at Risk
The loss of the akikiki is not an isolated event. It is part of a broader ecological crisis unfolding across Hawaii's remaining native forests. Kauai's other endemic forest birds face many of the same threats, and several are now dangerously close to extinction.
Among the most vulnerable is the akekee, another rare forest bird found only on Kauai. As of October 2026, only a few individuals were believed to remain in the wild. The outlook is also alarming for the anianiau and Kauai amakihi, whose populations are now estimated at fewer than 500 birds each. The Kauai elepaio also faces the growing threat of mosquito-borne disease.
These birds are part of an evolutionary heritage shaped by millions of years of isolation. Hawaii's native forest birds developed remarkable adaptations to the islands' diverse habitats, occupying ecological roles that include insect control and pollination.
Their disappearance represents more than the loss of individual species. It threatens to alter the relationships between birds, insects and native plants that help sustain Hawaii's mountain ecosystems. And as warming temperatures continue to push mosquito habitat higher into the mountains, the remaining birds may have fewer and fewer places to escape.
A Race to Prevent Further Extinctions
Despite the grim news from Kauai's forests, the akikiki has not disappeared entirely. A conservation breeding program established in 2015 has preserved a small population in human care. As of September 2026, 31 akikiki remained in captivity, offering a narrow but important opportunity for the species' eventual recovery. Conservation organizations, including the San Diego Zoo Wildlife Alliance and Honolulu Zoo, are working with state and federal wildlife agencies to protect the remaining birds and develop emergency measures for other threatened species.
But breeding birds in captivity is only part of the solution. For species such as the akikiki to return successfully to their native forests, the threat that drove them toward extinction must first be reduced. That means confronting the mosquitoes themselves.
Wildlife managers are pursuing expanded mosquito control as a critical component of Hawaii's forest bird conservation strategy. One promising approach involves releasing mosquitoes carrying incompatible strains of naturally occurring Wolbachia bacteria, which can reduce mosquito reproduction when released males mate with wild females.
Unlike conventional insecticide applications, this approach is designed to suppress targeted mosquito populations by interrupting their ability to reproduce. If successful at a sufficiently large scale, mosquito suppression could reduce avian malaria transmission and help restore safer habitat for vulnerable native birds.
Conservation breeding and the relocation of birds to safer habitats may provide additional protection while mosquito control efforts expand.
The Silence of the Alakai
For visitors who venture into Kauai's high mountain forests, the Alakai remains one of the island's most extraordinary natural environments. Ancient trees, thick mosses, native ferns and drifting clouds create a landscape that feels almost untouched by time.
Yet the forest is changing in ways that are not immediately visible. A mosquito is a tiny intruder in such a vast wilderness, but the disease it carries has helped unravel an ecosystem that evolved over countless generations.
The disappearance of the akikiki illustrates how climate change can magnify the damage caused by invasive species. Rising temperatures do not directly kill these birds. Instead, they help remove the environmental barriers that once protected them from a deadly disease.
The distinction matters because it points toward a possible solution. While reversing global warming is a long-term challenge, reducing mosquito populations and protecting vulnerable birds are actions conservationists can pursue now.
For the 31 akikiki surviving in human care, those efforts may determine whether their descendants ever return to the Alakai. And for Kauai's remaining native forest birds, the stakes could hardly be higher.
