The coqui is a tiny, coin-sized frog whose distinctive nightly mating calls are a beloved sound in Puerto Rico and other Caribbean islands. But people in Hawaii don’t share the same sentiment. The frogs have been growing in population in the state in recent years and are now starting to show up in larger numbers on Oahu – home to most of the state’s population. The frogs already have a strong foothold on the less-populated Big Island, and people there complain of being kept awake at night with a thunderous roar of chirps as thousands of male coqui simultaneously summon...