Influência do ruído urbano sobre a vocalização de Sporophila nigricollis (aves: thraupidae) na área urbana de Morrinhos, GO

Abstract

The rapid population growth in Brazilian cities has led to an intense process of urbanization, which has negative effects on various animal groups that inhabit these environments. Some characteristics of urban areas affect essential aspects of bird survival, and the noise produced by human activities has strong negative influences in their biology. In this study we sought to investigate the strategies used by a species of bird common in urban areas of Brazil, the Yellowbellied seedater (S. nigricollis) to avoid and song masking and optimize transmission. Spontaneous vocalizations of males S. nigricollis were recorded at 60 points of the urban area of Morrinhos (GO). The intensity of environmental noise (dB) was measured at every point just after each recording. Males sang song with had higher minimum frequencies in noisiest areas, the songs also had less trills and more unique syllables in the noisiest areas. Males also had smaller individual repertoires and plasticity of the frequency of one type of syllable. Our data suggests that strategies employed to adjust the song song were simplification of the repertoire, plasticity of frequency (long-term adjustment) and modulation of frequency in real time (shortterm adjustment). These results suggest that males of S. nigricollis change song components with increased noise, as well as help in understanding the success of this bird in urban areas.