By Fern Duvall, special to the Star-Bulletin
This tree frog, a species native to Mexico and
Central America, has established itself on Maui.

"That's the scary part because they're up in ohia and koa trees so the likelihood of feeding on native insects is very large," said state wildlife biologist Fern Duvall.

Duvall and other scientists say it's unknown at this time whether the tree frog will have a significant impact on the environment and that researchers are still trying to determine the species and its feeding habits.

Duvall said the sound emitted by it at night already has had an effect on the peaceful quality of living in rural Maui.

"The frog has a very loud, clear whistle, a high whistle followed by a lower one in quick succession," he said.

Duvall said the frog is from the genus Eleuthero dactylis. It's about a 11/2-inches long with its legs folded, and about four inches long with its legs extended.

The tree frog is a golden brown, with darker markings near the eye and a brilliant red orange in the folds of the back legs and underside.

Dr. Frederick Helm, the state's land vertebrate specialist, said the tree frog found on Maui is known as the dwarf barking frog and is found from Mexico through Central America.

"I would suspect it probably came in with some plants, probably bromeliads," Helm said.

Helm said most of the 600 to 700 species are nocturnal ground dwellers that hide during the day, but some species live on trees and bushes.

While no tree frog is native to Hawaii, a colony of alien Cuban tree frogs has been described as living in inland areas of Kaneohe the Koolau watershed on Oahu.

Helm said Pacific tree frogs from the northwest come in routinely on Christmas trees and he suspects there may be colonies of them in Hawaii.

While the Pacific tree frogs are allowed to be sold in pet stores, Cuban tree frogs and the barking dwarf tree frogs are illegal, Helm said.

A person convicted of importing illegal species into Hawaii may face a maximum penalty of $25,000 in fines and a year in jail.

Bishop Museum biologist Allen Allison said he worries whenever any alien species is introduced to the islands.

"You never know what it's going to do," Allison said.

Allison, who has been studying a specimen caught on Feb. 1, said the tree frog on Maui is the type that can lay eggs in moist soil and develop into a small frog.

"They do not have a tadpole stage," he said.

"Virtually, all frogs eat insects, and if this thing penetrates into the native forest, it will undoubtably eat native insects. Whether they'll eat enough to impact the native insect population, that remains to be seen. But the potential exists."

Duvall said he and entomologist Steve Montgomery heard the tree frogs in the Makawao forest at the 4,000-foot level in April 1996. But they were unable to find any.

Duvall said there also is a colony in Maliko gulch in Haiku and unconfirmed reports of tree frogs in the Kapalua and Wailea.

Duvall said a resident annoyed at the noise emitted by the tree frog caught one in the Omaopio area on Feb. 1.

Duvall said the tree frogs seem to be firmly established in some areas and they are difficult to reach because they are located high in the canopy of trees.

"I don't know how you'd go about a frog eradication," he said.