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DOES ENVIRONMENTAL TOLERANCE FAVOR SIGNAL VARIABILITY IN CALLS OF SONGBIRDS?

PI(s): Iliana Medina Guzman (Universidad de los Andes (COLOMBIA))
Start Date: 10-Jan-2012
End Date: 20-Mar-2012
Keywords: communication, adaptation, anthropogenic effects, comparative methods

It has been demonstrated that bird species in urban areas have broader environmental tolerances than nonurban species, possibly explaining their ability to overcome novel pressures of urban habitats. Though the degree of environmental tolerance may govern the presence or absence of species in certain places, behavior is also an important component that affects survival and reproductive success. Birds employ acoustic communication to attract mates, defend their territories or other purposes; thus, acoustic traits are under strong selection. In fact, not only signal receivers (e.g., mates) exert pressures on signal features, but also habitat, which favors only those signals that can transmit effectively through it. In this project I propose that because species that have broader environmental tolerances are exposed to a wider variety of acoustic environments (i.e., different background sounds), selection should maintain high signal variability that will transmit properly in a variety of acoustic environments. My aim is to test whether species with broader environmental tolerances also have higher levels of variation in their acoustic signals at the level of the individual and within species. To test this hypothesis I will use comparative phylogenetic methods using audio and climatic data available from online repositories. Additionally, I aim to test whether the breadth of signal variation may influence species tolerance to rapid human-induced environmental change. I propose that species with greater signal variation will be less sensitive to human-modified habitats and less prone to extinction. This study will help to the understanding of how some species succeed in urban habitats.