Finally, after years of planning, you've made it to Hawaii for your dream vacation. Stunning beaches, dramatic vistas, perfect weather. Hawaii truly has it all.

Wait, what's that noise coming from the forest? Whatever it is, it's loud; so loud that you're having trouble falling asleep at night. What's going on?

Frogs.

Coqui frogs, to be exact. They are tiny, seemingly harmless Puerto Rican tree frogs that made their way to Hawaii during the past decade as stowaways on potted plants. As often happens when there are no predators to eat the invading species, coqui frogs soon took over Hawaiian forests. Biologists such as Bill Mautz at the University of Hawaii at Hilo worry that the frog's voracious appetite for insects and spiders will disrupt the food chain, since many Hawaiian birds rely on the same source of food.

What's more, coqui frogs are very loud. Hotel guests usually complain that the frogs' chorus makes sleeping difficult. Mautz has measured the noise as peaking at 73 decibels. That's like trying to sleep in the middle of a loud party.

Hawaiian scientists and authorities have been hard at work trying to keep the coqui in check. Introducing a predator is not a safe option, since it, too, could reproduce to the point of becoming a problem. Caffeine is toxic for coqui and other frogs, but spraying forests with caffeinated chemicals hasn't done much to quiet the coqui so far.

Truth be told, there's no sure-fire solution in sight. For the time being, at least, coqui frogs will continue to enjoy their own Hawaiian vacation. As for human vacationers, bring ear plugs.