Millions of Altered Mosquitoes Could Save Hawaii's Birds

Ten million mosquitoes have been released over the Hawaiian island of Maui at a rate of 250,000 per week. Believe it or not, this isn't an effort to deter tourists, but rather one to save endangered birds. Many Hawaiian honeycreepers are disappearing due to avian malaria, a disease transmitted by invasive Culex quinquefasciatus mosquitoes that arrived in the 1800s. With no immunity, "native birds often die after a single mosquito bite," NPR reports. Some species have found refuge in the island's high-altitude forests, above 4,000 to 5,000 feet in elevation, where it was previously too cold for mosquitoes. But rising temperatures mean the insects are now advancing into these areas. The idea is to release modified mosquitoes that will help suppress the overall population.

The nonbiting male mosquitoes have been modified with a different strain of gut bacteria than is found naturally in Maui's female mosquitoes. If a female, who mates only once, chooses a mate with a different strain of bacteria than hers, their eggs won't hatch, meaning the overall mosquito population should shrink. The incompatible insect technique (IIT) has proven successful elsewhere. On two islands in China, IIT cut dengue-carrying mosquito populations by 90%, per Scientific American. The Birds, Not Mosquitoes coalition—made up of the National Park Service, the state of Hawaii, and nonprofits including the Maui Forest Bird Recovery Project—hopes to see a drop in the mosquito population after the summer.

That should translate to better outcomes for honeycreepers, which are culturally significant and vital to the ecosystem, per the Nature Conservancy. Only 17 of 50 species remain in the wild, and some are expected to go extinct in the wild as early as this year. Inside the mosquito-screened buildings of the Maui Bird Conservation Center, officials are trying to save what are now some of the rarest birds in the world, representing the very last of their species, including the 'alala. Through breeding programs, they hope to welcome chicks that can later be released into the wild. It's all rather challenging. But "the only thing more tragic than these things going extinct would be them going extinct and we didn't try to stop it," Chris Warren, forest bird program coordinator at Maui's Haleakala National Park, tells NPR. (More endangered species stories.)