Oahu's peaceful nights are in danger from a very small source -- the coqui frog.  It has already infested the Big Island and experts say it will cause big problems here if it isn't stopped.

But now, there is an island wide effort to combat the coqui.

Suzanne Case and her nieces heard the sound of the coqui before -- in Hilo.

"Once you've heard it, it's a remarkable sound and volume and shrill.  It drowns everything out.  It's hard to talk sometimes," said Case.

It's a sound they don't want to hear in Makiki.  So, as they walked around they listened for coqui.  It's part of the evening's effort to get more people involved in locating the invasive species on Oahu.

"These frogs can be anywhere and we're a small organization so we need their help to tell us where the frogs are," said Rachel Neville from the Oahu Invasive Species Committee.

Along with listening, Case also used the Honolulu 311 app to let the experts know this part of Makiki was all clear.

"I know that sending in information whether you hear or not, helps to map it out," said Case.

But the effort to stop the invasive species doesn't end.  More work must be done to keep the tiny frogs from spreading.

"Because the Big Island is so infested, the frogs can come over in anything that has enough water so they can survive the journey," said Neville.