Chickens believed to silence noisy Big Isle coquis' cries
A UH researcher will test residents' claims of predatory behavior
Jean BezanMarquez hears the chirps of coqui frogs coming from her neighbor's coffee farm in Honaunau on the Big Island but none around her home because, she says, wild chickens keep them away.
BezanMarquez said the chickens are attracted to her home because her husband feeds wild birds. Dogs keep the chickens away from her neighbor's property.
Big Island Councilwoman Virginia Isbell says there are no coqui in her Kealakekua neighborhood.
"And that's because the wild chickens take care of them," Isbell said. "Once in a while I'll hear a coqui frog in the evening, and the next evening I don't hear it again because those chickens are out there scratching away during the day when the coqui frogs are sleeping down below."
Entomologist Arnold Hara, from the University of Hawaii's College of Tropical Agriculture and Human Resources, has heard many similar reports. So much so that he's decided to do an experiment to see if chickens prey on coqui.
Hara has been studying coqui under a U.S. Department of Agriculture grant to see if the same principles for controlling insects can be applied to the small frog with the big, piercing chirp.
UH-Hilo herpetologist William Mautz has been working with Hara, studying the coqui invasion in Hawaii under a National Science Foundation grant. He said it wouldn't surprise him if chickens as well as mongoose eat coqui, "because coqui come down to the ground during the day, when mongoose and chickens hunt."
Coqui is a tree frog that is active at night.
In a recent study that examined the digestive tracts of rats, mongoose and cane toads caught in Lava Tree State Monument in Pahoa, an area densely populated with coqui, only mongoose were found to feed on coqui. And coqui bones were found in only three of the 22 mongoose.
During a population-density study of coqui in different parts of the Big Island, Hara and Mautz reported that a rat was spotted with a coqui in its mouth.
And there have been reports of cats catching coqui and bringing them home, said Kyle Onuma, of the state Department of Agriculture's Plant Pest Control Branch.
In the coquis' native Puerto Rico, land crabs, spiders, tarantulas, scorpions and snakes prey on the frog.
But there is no evidence of chickens eating coqui, Hara said. And he points out that there are many wild chickens on Kauai, but the coqui was still able to establish a population there.
Sherla Bertelmann says she has seen chickens catch and eat coqui on her plant nursery in Keaau. She says she feeds dead coqui to her chickens.
"And I'm not the only one," she said.
Bertelmann said the chickens developed a taste for coqui after her husband introduced dead coqui to their feed. And now her chickens and wild chickens that frequent her property catch and eat coqui.
Even if chickens do prey on coqui, it wouldn't be enough to make a difference on the overall population of coqui in Hawaii, Mautz said.
"All it can do is help us around our own area," she said.
She still takes all the recommended actions to control coqui on her property -- spraying citric acid and hydrated lime, setting PVC and bamboo traps to catch frog eggs and clearing areas that can harbor coqui.
So far, the control measures have kept the coqui at a distance and their chirps are more tolerable now than when they are right outside her window. She calls their distant chirps "sleigh bells."
BezanMarquez said her neighbor likes coqui and hears a voice or two from down the road. But she said the volume of the coqui is "at a charming level."
As for the noise roosters create, BezanMarquez says she sleeps through their crowing.