Species vary enormously in the complexity of their vocal repertoire. Unfortunately, we know very little about how this variation is matched by auditory capabilities. Moreover, individuals can vary enormously in how much their vocal repertoire changes over the course of the year, yet we know almost nothing about correlated changes in auditory capability. This comparative study of the plasticity of the auditory system will give us insight into both of these issues. This research program will focus on properties of hearing in songbirds using auditory evoked potentials, how those properties change across seasons, and how they differ between individuals. The research will include an unprecedented array of tests of hearing performance in eight species of songbirds.. First, the experiment will test whether hearing is ?tuned? to species-specific aspects of song, and the characteristics of the species habitats, and if hearing is conserved among closely related species. Experiments will also test whether individuals vary more when processing song than when they process contact calls. Second, the experiments will evaluate whether seasonality in hearing matches the use of vocal signals, habitat changes that affect how sound carries through an environment, follows taxonomic similarities between species, and whether seasonality reflects seasonal variation in social interactions.
Broader Impacts Given the broad similarities between avian and mammalian auditory systems, understanding the plasticity of the avian auditory system is likely to help us understand plasticity in the human auditory system, and thereby provide avenues of research in the treatment of hearing disorders. Our work on hearing has been the focus of a series of workshops on communication geared to high school students. One goal of this program is explicitly to include students from disadvantaged areas. We will also train graduate students and undergraduates in cross-disciplinary research.