The term “opioid bird” refers to one of Hawaii’s most iconic native species: the I’iwi. Known for its brilliant scarlet plumage and unique song, the I’iwi is a symbol of the islands’ rich biodiversity. This bird inhabits high-elevation forests but is facing a severe threat that has pushed it toward extinction, prompting urgent conservation efforts.
The I’iwi and its Peculiar Nickname
The I’iwi, or scarlet honeycreeper, is one of Hawaii’s most recognizable native birds. Adults are a brilliant vermillion red with black wings and a tail, and they possess a long, salmon-colored bill curved to drink nectar. This specialized bill is adapted for sipping from native tubular flowers, making the bird a pollinator in its forest ecosystem. As the I’iwi moves between flowers, it transfers pollen, a process fundamental to the reproduction of these native plants.
The nickname “opioid bird” has nothing to do with drugs, but stems from the bird’s unusual and varied vocalizations. Its call is often described as sounding like a rusty gate hinge, a series of gurgles, whistles, or the sound of a squeaky toy. Beyond its sound, the I’iwi holds deep cultural significance for Native Hawaiians. Its red feathers were highly prized and used to create cloaks, helmets, and leis for royalty, symbolizing power and prestige.
The Threat of Avian Malaria
The primary threat driving the I’iwi toward extinction is avian malaria, a disease caused by the parasite Plasmodium relictum. This disease is transmitted by the invasive southern house mosquito (Culex quinquefasciatus), introduced to the islands in the 1800s. Having evolved in an environment free of mosquitoes, Hawaiian honeycreepers like the I’iwi have no natural immunity to this disease. For an I’iwi, a single bite from an infected mosquito leads to death in over 90% of cases.
This disease has already contributed to the extinction of numerous other Hawaiian forest birds. The I’iwi has survived by retreating to high-elevation forests above 4,000 feet, where colder temperatures historically prevented mosquitoes from establishing populations. However, this refuge is now shrinking due to climate change. As global temperatures rise, mosquitoes and the malaria parasite can survive at higher elevations, invading the I’iwi’s remaining habitat.
Innovative Conservation Strategies
Conservationists are deploying a strategy known as the Incompatible Insect Technique (IIT) to combat the mosquito population. This method involves rearing male southern house mosquitoes in a laboratory and introducing a specific strain of the bacterium Wolbachia. These lab-reared males are then released by the millions, sometimes from helicopters or drones, into the I’iwi’s high-elevation habitat.
The Wolbachia strain in the lab-reared males is incompatible with the strain carried by wild female mosquitoes in Hawaii. When the modified males mate with wild females, the females’ eggs are not viable and fail to hatch, leading to a decline in the mosquito population. Since male mosquitoes do not bite, these large-scale releases pose no additional risk to birds or humans. This strategy is part of the “Birds, Not Mosquitoes” initiative and functions as a targeted biopesticide.