Prior to the arrival of the first whaling ships, blood-sucking insects were unknown in Hawaii. The first mosquitoes to arrive on the Islands were carriers of avian malaria, which can decimate bird populations. Over the next 150 years, four more mosquito varieties were introduced into the islands, all of which can, and do, carry diseases affecting humans. 

Sadly, Hawaii’s bird population remains in decline. Out of over a hundred native bird species fewer than fifty remain, with most of that number counted as endangered. Invasive species of all kinds have a role in the dangers to native birds, but mosquitoes carrying avian malaria have been, and remain, the principal threat to our birds.

All mosquitoes feed on plant nectar, however, female mosquitos also need protein to reproduce which is why the females feed on blood as well as nectar. The females fly up to 14 miles each night, hunting by detecting body heat and the carbon dioxide we all breathe out.  

Without some kind of mosquito control, Kauai’s bird population will continue to shrink. Indeed, all Hawaii is at risk. 

No amount of swatting or spraying over the past one-hundred years has halted, or even slowed down, the relentless mosquitoes. On the contrary, they are thriving. 

Now science is helping to control and suppress mosquito populations. Researchers have found that releasing only male mosquitoes that have been made sterile by irradiation or an insect-specific bacteria can cause a huge dip in mosquito numbers. When males carrying the bacteria Wolbachia mate with females, the bacteria prevents the eggs from hatching. The males made sterile by irradiation can mate with females but cannot impregnate the female. Either way, a halt to successful mosquito breeding gives our endangered birds the advantage.

For over a decade, The Kauai Forest Bird Recovery Project has concentrated on studying the impact of mosquitoes on indigenous forest birds. In October of 2023, the Project released about 20,000 male mosquitoes carrying the Wolbachia bacteria into the upland forests of the island. The male mosquitoes will be tracked, by use of traps, to document how they disburse throughout the landscape. This information will be incorporated into future releases to ensure success.

There are a few simple actions we can all take to help our birds and to support the work of the Bird Recovery Project.

Because mosquitoes breed in soft, moist soil or stagnant water, replace all standing water at least once a week. 

Remove trash from around any standing water

Finally, for your safety, use insect repellent containing DEET on exposed skin anytime you’re around mosquitoes. DEET doesn’t kill the mosquitoes. It just disorients them, so they go elsewhere for food.

Kauai without birds or birdsong? Not if we can help it!