They’re very, very quiet — until they’re not — and good at being unseen as well as unheard. And now an infestation of the tiny coqui frogs with the big voices on about an acre in Waimanalo has reignited the fervor of state agricultural inspectors to eradicate them.

Coquis tend to make their loud, distinctive calls at night, and favor areas littered with dead leaves and other debris where they can hide. Bottom line: If they’re seen or heard, it’s best to call the state experts for help: 643-PEST (7378).