Boom boxes in the wilds of Florida weren\'t there for entertainment but as part of a study of how bird species react to the sounds of predators, researchers say. University of Florida researchers set up camouflaged above-ground boom boxes on half-acre plots at the Ordway-Swisher Biological Station near Melrose to broadcast predator bird sounds, and discovered smaller birds listen to vocal cues to avoid areas populated by those predators. Powered by car batteries, the boom boxes were programmed for four months to broadcast predator sounds on a schedule simulating when and how predators would normally call. \"Such broadcasting was to create the perception for forest birds that there was increased abundance of predators in the forest,\" doctoral student Fangyuan Hua said. \"We were very interested in knowing whether forest birds that are prey to these predators would use such cues and respond by altering their decision about where to breed.\" While some bird species clearly avoided plots with feared predators, other species seemed to alter their behavior to make themselves less conspicuous, the researchers said. \"Results from this study are exciting because they support growing understanding that animals are using acoustic cues to make important survival decisions,\" study co-author Kathryn Sieving, a professor of wildlife ecology and conservation, said. \"Species actually listen to each other and predators\' calls to detect whether a predator is lurking nearby.\" An emerging field of \"soundscape ecology\" is focused on understanding how animals rely on natural sounds, she said. \"So, we are learning that we can\'t just protect natural habitat for wildlife, we have to protect natural soundscapes, too, which is difficult for us noisy humans with all of our planes and trucks and oil rigs and fracking machines,\" she said.