BIRD SONG: THE INTERPLAY BETWEEN URBAN NOISE AND SEXUAL SELECTION

Abstract

Ambient noise is present almost everywhere in the biosphere. Because background noise can potentially mask the acoustic signals that many animals use to communicate, many species may face a problem when trying to get their messages through noisy environments. Here I reviewed some of the strategies that birds use to deal with ambient noise, and related this information to the possible consequences that may result when birds use their songs in the context of sexual selection, a process that has been widely acknowledged as a main force shaping the evolution of bird songs. I suggest that, depending on the species-specific nature of the sexual selection process in relation to the sender songs, ambient noise may impair the probability of reproduction to different degrees in different species. For instance, species whose songs are effective at communicating in noisy environments, but at the same time render the sender a lowered probability of attracting a mate and defending a territory, may face a greater reduction in reproductive success than if the sender's songs fail in one aspect of sexual selection (e.g. female attraction), but not in the other (e.g. male-male competition). However, more studies are needed if we are to obtain a clearer picture of the possible outcome that may result from the interaction between ambient noise and sexual selection. Some questions that need answers are: to what extent ambient noise impairs the processes of sexual selection in nature? Are sub-oscines equally vulnerable than oscines?