|Auditory processing of distance-degraded songs by songbirds: linking mechanism and behavior|
|Amy V.H. Strauss1, Luke Remage-Healey1,2,3, Jeffrey Podos1,4. 1University of Massachusetts, Graduate Program in Organismic and Evolutionary Biology, Amherst, MA, United States; 2University of Massachusetts, Department of Psychological and Brain Sciences, Amherst, MA, United States; 3University of Massachusetts, Center for Neuroendocrine Studies, Amherst, MA, United States; 4University of Massachusetts, Department of Biology, Amherst, MA, United States
Acoustic signals are useful for animals that communicate over distance or beyond visual range, as they enable long-distance interactions in real time. As sounds propagate from senders to receivers, they are subject to distance- and habitat-dependent structural degradation, leaving an acoustic signature that may provide receivers with information about singer location. The precision with which receivers can use this to assess singer distance should depend on their perceptual discrimination abilities, which we tested in two parallel experiments with song sparrows. In field trials, we tested the behavioral responses of males to playback of conspecific songs recorded at near and far ranges. In lab trials, we presented these stimuli to anesthetized birds and measured neurophysiological activity in forebrain nuclei known to function in auditory discrimination. Results indicate that birds’ behavioral responses did not vary with degrees of stimulus degradation, suggesting that song sparrows do not rely solely on acoustic cues to determine signaler distance. Ongoing experiments are evaluating the extent that birds’ auditory processing nuclei can discriminate songs from different distances.