Bird experts offer native honeycreepers a lifeline on Kauaʻi

Warmer climates in recent years have allowed mosquitoes to move to higher elevations, increasing the risk of disease to native forest birds such as the ʻakikiki and ʻakekeʻe, two critically endangered native Hawaiian honeycreeper species.

The ʻakikiki could disappear from the wild this year because of mosquito-borne avian malaria, with ʻakekeʻe not far behind.

While conservation partners wait for final approval of a proposed mosquito birth control, known as the incompatible insect technique, bird experts on Kauaʻi are stepping up their use of other, more traditional tools to give the native birds a lifeline.

Aug. 8 is designated as Hawaiian Honeycreeper Day in Hawaiʻi. It’s also when a team from the Kauaʻi Forest Bird Recovery Project will take to the skies to expand the use of two naturally-occurring bacteria, Bacillus thuringiensis (sold commercially as “Dunk”) and Bacillus sphaericus, to prevent mosquito larvae from hatching in the uplands of Kauaʻi.

The bacteria are harmless to humans but deadly to mosquito larvae. They’re found in soil worldwide and widely used in organic agriculture and water treatment. While project staff have used Bacillus to control mosquito larvae for years, it has traditionally been applied by hand while hiking across the many streams and valleys of the Alakaʻi wilderness. Adding an aerial approach allows the team to address a larger area and hopefully save more birds.

“The increased use of Bacillus should provide a stopgap for ʻakeke’e, allowing the species to avoid extinction long enough to benefit from the proposed mosquito birth control tool,” said Cali Crampton with the Kauaʻi Forest Bird Recovery Project. “Both Bacillus and the [incompatible insect technique] birth control use bacteria to suppress mosquitoes. The two tools are separate but work together to address different parts of the mosquito life cycle: the Bacillus bacteria kill mosquito larvae, while different strains of the Wolbachia bacteria used in [the incompatible insect technique] result in unviable eggs that never hatch into larvae.”

While conservation partners are currently focused on helping birds, people should also see benefits from increased efforts to suppress mosquitoes in Kauaʻi’s mauka regions.

The combined use of organic bacteria and other integrated pest management efforts, such as fixing potholes in roads and overturning containers of standing water, should help popular hiking and camping areas in Kōkeʻe and the Alakaʻi to once again become mosquito-free.