Hawaii’s mosquito problem has long been a headache for authorities. These pests not only spread diseases but also cause catastrophic damage to Hawaii’s ecosystem, with some forest birds facing extinction due to diseases transmitted by mosquitoes. Yet, authorities have now deployed drones and helicopters to release more mosquitoes in Hawaii, a puzzling move that has left many scratching their heads.
The mosquitoes being released from drones are not your ordinary blood-sucking pests – they are laboratory-cultivated male mosquitoes that do not bite and carry a specific bacteria. This bacteria, when passed on to wild female mosquitoes through mating with the male ones, renders the eggs laid by the female mosquitoes unable to hatch. Over time, with repeated releases, the population of mosquitoes in the wild is expected to gradually decline. This strategic approach is hoped to help control the influx of invasive mosquitoes in Hawaii, which pose a threat to the survival of some local bird species.
Hawaii was once home to over fifty species of honeycreeper birds, colorful little birds that populate the native forests and hold significant cultural importance in Hawaiian heritage. However, their situation has become increasingly worrying. The forests are now becoming quieter with only 17 honeycreeper species remaining, most of them on the brink of extinction.
Honeycreepers are disappearing due to avian malaria spread by mosquitoes. The local native birds have no immunity to this disease and often succumb to it after just one mosquito bite. Last year, a gray bird species named ‘akikiki’ was on the brink of extinction in the wild, with the yellow-green ‘akeke’e estimated to have fewer than 100 individuals left.
According to CNN, while deforestation has impacted bird life, Chris Farmer, the Hawaii program director for the American Bird Conservancy (ABC), stated that the primary “threat to their survival” comes from the avian malaria spread by mosquitoes.
These mosquitoes are not native to Hawaii but were first discovered in 1826, likely inadvertently brought to the islands by whaling ships. Currently, there are eight invasive mosquito species in Hawaii.
“They (mosquitoes) have triggered wave after wave of extinction in [bird species],” Farmer said, emphasizing that many local birds like honeycreepers have no resistance to this disease.
He explained that as mosquitoes thrive in the warm tropical habitats of low-altitude islands in the Hawaiian archipelago, the remaining honeycreepers have sought refuge in the higher mountainous regions of islands like Maui and Kauai. However, this situation is changing as temperatures rise in the mountains, causing mosquitoes to move uphill, leading to a sharp decline in bird populations in places like Kauai.
“If we don’t break this cycle, we’ll lose our honeycreepers,” he added.
National Public Radio (NPR) cited Chris Warren, the forest bird project coordinator at Haleakala National Park in Maui, in a report last June, stating, “We are in the midst of a continuing [bird] extinction crisis.”
“The only thing more tragic than these species going extinct is that they’re going extinct, and we’re not even trying to stop it from happening,” Warren lamented.
Conservationists have been searching for solutions to control mosquito populations and provide a lifeline for honeycreepers. However, Farmer noted that dealing with the mosquito issue on a landscape scale is challenging. Using insecticides could harm essential local insect populations vital to the ecosystem.
After years of research, conservationists have finally found a solution – “mosquitoes to control mosquitoes.”
In 2023, helicopters began releasing laboratory-cultivated male mosquitoes carrying Wolbachia bacteria into honeycreeper habitats in Maui. This bacteria is used to suppress mosquito reproduction.
“We have a rough estimate of mosquito numbers in the wild, and we are trying to release male mosquitoes carrying Wolbachia bacteria at a rate ten times higher than that, so they can find female mosquitoes to mate with, and the female mosquitoes’ eggs won’t hatch,” Farmer explained.
“Currently, we release 500,000 mosquitoes per week in Maui and 500,000 mosquitoes in Kauai,” he added.
Honeycreepers are an integral part of Hawaii’s local ecosystem. These birds help pollinate native Hawaiian plants, prey on insects, and maintain forest health. These forests, in turn, filter rainwater and provide drinking water for many communities.