HONOLULU - During every Thursday evening get togethers in Waim?nalo, people gather at sunset to search for invasive frogs. Coqui frogs, known for their loud chirp, are a major forest and agricultural pest.

Community members, volunteers and staff from the DLNR Division of Forestry and Wildlife (DOFAW), the Hawai?i Department of Agriculture (HDOA) and the O‘ahu Invasive Species Committee (OISC) are on a mission to remove as many coqui frogs as possible from the state lands they’ve invaded.

The group hikes through muddy and steep terrain, listening for the frogs’ calls. When they spot one, they hand capture it, or trap it in a long tube. Then the frogs are transferred to a holding container and sent to HDOA, which records data such as numbers of males and females, juveniles and babies.

The location of each captured frog is logged in order to track the spread – or reduction – of the population. When several frogs can be heard in an area but none are seen, citric acid is sprayed over the foliage. “The citric goes through their skin, and it irritates them, basically, and they either move away, or they actually die from contact with the citric,” explained DOFAW Field Technician Ryan Chang. “Citric denatures (degrades) very rapidly. Once it hits the surfaces of the soil or plant material, it doesn’t stay in the environment very long.”

The coqui frog, native to Puerto Rico, was accidentally introduced to Hawai?i in the late 1980s. Since then, it has become a significant invasive species. The small, nocturnal frogs are known for their loud, distinctive “co-qui” calls, which can reach up to 95 decibels, roughly the noise level of a motorcycle engine.

Their presence disrupts the delicate balance of Hawai?i’s native ecosystems, harming native wildlife such as the endangered ??pe?ape?a (hoary bat) and pueo (Hawaiian short-eared owl) that rely on their acute hearing to hunt. In Hilo where the coqui population is well-established, forest surveys show a lack of native insects, their numbers decimated by the frogs.

Coqui frogs pose a wide range of impacts beyond just the loss of biodiversity. Their incessant calls disrupt the peace and quiet of Hawai?i’s natural landscapes. “I think one of the more devastating things is the soundscape of Hawai?i is changing. There’s rain names, there’s wind names, and those things, you know, they’re changing with invasive species, especially coqui frog,” said Chang.

Kimeona Kane, a lineal descendant of Waim?nalo who spent his childhood in these forests, remembers a time when there were no coqui cries at dark. Now he joins the hunt every week and shares his cultural perspective with the volunteers. “There’s some comments that people have shared that we’ll get used to it. We shouldn’t have to get used to something that wasn’t here,” he said. 

“I think one of the biggest messages that we want people to recognize and understand is, it is all of our kuleana to move in these ways. It cannot just be a blame game. It can no longer be a resource deficiency game. It has to be something that we advocate stronger for, make considerable changes to, and hold the accountability line across all levels,” Kane added.

Collaborative efforts like this, involving the HDOA, OISC, DOFAW and volunteers are essential in curbing the invasive population. “We have volunteers that come every single week, and they notice how things are changing,” Chang said.

Community members of any age are encouraged to participate – the second and third Thursdays of each month are nights for less-experienced hikers. “For keiki, they come out and build pilina, or relationship with  the place,” explained Chang. “K?puna, they want to see that we’re being present in these spaces and trying to eradicate this invasive species.”