Bishop Museum
The alien tree frogs are generally less than 2 inches in size,
and they are hard to find. Their ear-piercing whistles,
measuring 90 to 100 decibels, belie their small size.

Tiny tree frogs
cause big problems
for wildlife

Caribbean invaders threaten
native species, emit ear-
|piercing whistles

By Gary Kubota
Star-Bulletin

WAILUKU -- Wildlife officials are worried an invasion of alien tree frogs is hopping out of control on Maui and the Big Island and threatening native forests.

Five new sites have been found on the Big Island in the Puna and Hilo districts, state officials announced yesterday.

Experts say besides their irritating ear-piercing sounds, tree frogs threaten to compete with native forest birds for insects and could spread parasitic worms that kill nursery plants.

The frogs, native to the Caribbean and first introduced about eight years ago, were spread on Hawaii and Maui through plants and soil obtained from infected nurseries.

They're generally small, about a half inch to 2 inches in size, and difficult to detect because they usually remain under the leaves of plants during the day.

Their presence becomes known because of the loud whistles they emit -- about 90 to 100 decibels, or the sound of a shrill generator.

Three different species of tree frogs exist on Maui and two on the Big Island. One species has been found on Oahu.

Scientists warn the frogs can form dense populations rapidly. In native rain forests, one of the species has been known to exceed 8,100 animals in an acre.

A task force on Maui is seeking $293,000 from the state Legislature to control alien species, including the tree frogs.

On the Big Island, biologists have begun field testing the use of detergents to kill the alien frogs.

Fred Kraus, alien species coordinator for the state Department of Land and Natural Resources, said officials are testing detergents that have already been approved for field use by the federal Environmental Protection Agency.

Kraus said the state will need more field workers to conduct an eradication program.

Michael Buck, administrator for the state Division of Forestry and Wildlife, said a key in the fight against the tree frogs is financial support from lawmakers.

"These frogs can be a serious pest and a growing threat to native species of birds, insects, plants and to agricultural nurseries," Buck said.

"We are working closely with other resource agencies to ensure close coordination of responses."

Wildlife officials are continuing to monitor the locations of the colonies and are asking people to call to report any frogs.

The hot line on the Big Island is 1-808-974-4375 and on Maui, 1-808-871-2929.