|Atlantic Forest birds and their acoustic responses to urban noises|
|Lilian Manica1, Eduardo Brandt1,2. 1Departamento de Zoologia, Universidade Federal do Paraná, Curitiba, PR, Brazil; 2Programa de Pós-graduação em Zoologia, Universidade Federal do Paraná, Curitiba, PR, Brazil
Environmental noise can damage animal acoustic communication. In urban areas, industrial activities and traffic are the main noise sources, which may impact birds that change their vocalizations to prevent sound masking and negative consequences to territory defense or mate choice. We tested if bird vocalization varies according to the level of anthropogenic noise in a Brazilian city and its surrounding rural areas within the Atlantic Forest domain. We recorded 173 sounds of four species, all paired with their respective local noise levels which we measured using a sound level meter. We analyzed noise effects on duration, peak frequency, and minimum and maximum frequencies of bird notes and songs. We found all species changed at least one of their sound parameters; in noisier environments, Rufous-collared Sparrow, Saffron Finches and Great Kiskadee increased their note frequencies while Rufous-bellied Thrush reduced their frequencies. The Great Kiskadee also produced longer songs when noises were high. We suggest these birds are likely maximizing the transmission of their signals according to the environment in which they live, but noise effects varies according to each species.