The Acoustic Chorus and its Ecological Significance

The chorus, vocalization of animals which occurs at dawn and at dusk, has perplexed scientists for decades and it remains an enigma in terms of adaptation, fascinating generations of bioacousticians and ethologists. The time of chorus is strongly related to breeding periods or to feeding or territorial activities. The acoustic transmission hypothesis (ATH) is that birds sing most intensively when song is not distorted by air turbulence and not masked by anthropogenic noise. Songbirds are active participants in both dawn and dusk choruses. Choruses are extensively used by amphibians and the sonic network is more complex than simple interindividual acoustic competition. Although the role of chorus activity in marine animals is poorly understood, several researchers have emphasized the important role of this phenomenon as a source of information for different species. Evidence shows that choruses are depressed by disturbance events like wind or rain and by human technophonies.