The south and west sides of Maui boom with noises one would readily expect to find in the islands: wind, waves, and the occasional lulling strain of an ukulele.
But venture upcountry and you’ll be privy to a whole new part of the tropics. Rural and rustic, the only noise in these parts comes straight from nature—from the chirps of chatty birds to the electrical pulse of insects.
Of those sounds is the twitter of coqui frogs, an invasive species that may be elusive in sight but is palpable in the clatter they create.
That sound comes in the form of a peep that’s much like the frog’s name: a high-pitched Ko-KEEE that produces a chorus that’s equal parts enchanting and maddening. Considering that the coqui frog is no larger than a quarter, theirs is an oversized voice if there ever was one, with male frogs hitting 90 decibels—about as loud as a vacuum cleaner or lawn mower. Indeed, National Geographic named the coqui the noisiest amphibian on Earth.
The coqui frog is believed to have hitchhiked a ride to the Hawaiian Islands on a shipment of potted plants that arrived from Florida in 1988.
Originally from Puerto Rico, these brown-skinned wonders took to the islands like they had always been here; today, Hawaii has three times the population of coqui frogs than the Spanish’s Isle of Enchantment.
Much of this is due to the aloha spirit they found within in Hawaii’s gentle ecosystem.
Given Hawaii’s unique location in the Pacific—which renders it the most isolated archipelago in the world—the species here don’t have to defend themselves against the usual threats in nature. In the absence of predators like tarantulas and, more specifically, snakes, the coqui frog was and is able to proliferate widely—so widely in fact that, today, large frogs devour their smaller kin. Coqui frogs also found numerous crevices in which to hide out on the main islands, namely in the form of the abundant lava rocks that are seen throughout Hawaii.
But the Hawaiian ecosystem is as fragile as it is gentle.
Coqui frogs feed on plants and insects that are essential to pollination; given the size of the frogs’ population, they put vital flora and fauna at risk of extinction. What’s more, coquies’ ravenous appetites make them competitors of endemic birds and the endangered Hawaiian fruit bat, and have already done considerable damage to Hawaii’s forest floors and treetops. And one seemingly minor change in the ecosystem can create a domino effect, changing the natural landscape of the beloved Aloha State. Moreover, scientists worry that coquies may serve as a viable food source if the brown tree snake is ever inadvertently introduced to Hawaii.
The response to the prevalence of coqui frogs in Hawaii has been gaining traction in recent years.
Now, it’s illegal to transport the frequent breeder, even unintentionally (in other words, double-check that backpack before going through security). Entomologists are experimenting with caffeine spray—which have a lethal impact on frogs’ hearts—while irradiation is being used to sterilize males. Additionally, dock workers are trained to keep an ear out for the telltale Ko-KEEE when sending and receiving shipments, and methods are in place to protect plants from the coquies’ appetite. Coqui wands—essentially frog nets—are utilized to contain the population on Oahu, citric acid is employed to kill eggs statewide, neighborhood coqui watches have assembled on the Big Island, and real estate values typically decrease with the presence of coqui populations. And while it may take years to see the long-lasting consequences that coqui frogs will have on the native ecosystem, their discernible cries—which last from dusk till dawn—are often lamented by locals. This is particularly true on the Big Island, which is considered one of the quietest inhabited places on the planet—so much so that the Mayor of Hilo declared a coqui state of emergency in 2004.
Such is not the case in Puerto Rico.
There, coqui frogs—otherwise known as Eleutherodactylus coqui—are nothing short of worshipped. (Some account for this by pointing out that Puerto Rico is naturally a louder place, rendering that Ko-KEEE less a nuisance than a soundtrack for Puerto Rican lives.) Menudo named a popular hit after them. Plush toys bear their resemblance. Johnny Depp’s The Rum Diary—which was filmed in Puerto Rico—features the coquies’ cries in night scenes. Stone engravings carry their image. And if a Puerto Rican ever wants to express their nationality, they’ve been known to say “Soy de aquí como el coquí“—or “I’m as a Puerto Rican as a coqui.”
As acclimated as coquis may be to the islands of Hawaii and Puerto Rico—and as adaptable as they’ve demonstrated to be to different ecological zones—they’re decidedly landlubbers.
The small tail with which they’re born quickly disappears, and their lack of an inter digital membrane renders them unable to swim (which gives their name—Greek for “free toes”—even more veracity). And while coqui frogs, which were once considered exotic in Louisiana and Massachusetts, tend to live no longer than a year, they reproduce rapidly through terrestrial eggs that, unlike most frogs, don’t go through a tadpole stage. Fathers adore their progeny, often staying with their hatchlings to shield them from predators and to keep them properly moistened.
The rapidity of those reproductive powers is felt throughout their primary habitats of Puerto Rico, the Virgin Islands, the Dominican Republic, and Hawaii, but they’ve taken most to the Big Island, where one can find more than 10,000 coqui frogs within a single acre.
Naysayers may be as prominent in Hawaii as the tiny species, but other Hawaiian residents welcome their amber-eyed presence—in large part because they feast on flies, mosquitoes, and fire ants. One such resident is a biologist named Sydney Ross Singer who, together with his wife Soma Grismaijer, have created a coqui sanctuary in Pahoa. Ross is so entranced by the coqui, in fact, that he has a recording of their nighttime calls to take with him on his travels.
Should you be traveling throughout Hawaii, keep your ears attuned to their lilting chirp, particularly after a rain.
It may not be the lulling strains of an ukulele in south and west Maui, but it’s one of the purest sounds of Hawaii.
Photos courtesy of Hawaii Photographers.