However, as noise pollution interferes with animal communiqués all across the globe, many animals' ability to communicate effectively comes under fire. Increased shipping traffic over the last century has dramatically affected the transfer of whale song around the ocean basin. Studies have found that songbirds, too, suffer from noisy (albeit terrestrial) urban environs. Some species have had to modify their singing styles, producing songs that are louder and shriller, in order to be heard above the clamor. Pumped up volume usually leads to simpler and somewhat inferior styles of singing that female birds seem to find decidedly less sexy.