Date of Award

5-2015

Degree Name

Doctor of Philosophy

Department

Biological Sciences

First Advisor

Dr. Sharon Gill

Second Advisor

Dr. Steve Kohler

Third Advisor

Dr. Maarten Vonhof

Fourth Advisor

Dr. Koorosh Naghshineh

Abstract

The spread of high-amplitude anthropogenic noise across natural landscapes is a serious issue for vocally communicating animals. Noise disrupts communication, which has implications for individual fitness and population persistence. In response, animals adjust their vocal signals with increasing noise. As the increase in noise has occurred on a relatively short time scale, evolutionary responses are likely not the primary cause of adjustments. Instead, short-term behavioral adjustments may drive population differences; however, such adjustments are currently not well understood. Moreover, noise is only one characteristic of urbanized landscapes and whether other characteristics, such as highly reverberant surfaces interact with noise to affect signal structure is unknown. Finally, whether animals adjust other aspects of communication such as selective space use when signaling to improve communication is unknown. In this study, the effect of anthropogenic noise and urban structure on the singing behavior of chipping sparrows (Spizella passerina) in southwest Michigan was studied using observations of singing individuals, as well as experimental manipulation of the sound environment around preferred singing perches. The objectives of this study were: 1) to examine how males adjust song structure in relation to noise and urban structure; 2) to explore the ability of individual males to rapidly adjust their signals based on moment-to-moment noise variation; 3) to develop methodology for mapping spatial variation in noise in order to 4) assess whether males adjust their use of space within their territories in response to spatial variation in noise. Results indicate that: 1) males adjust song structure with increasing noise and structure, an effect that is modified by underlying song structure; 2) males show rapid and unique individual song plasticity to variation in noise in the seconds before singing; and 3) males abandon preferred singing perches under the loudest noise conditions, potentially indicating a threshold of noise tolerance.

Access Setting

Dissertation-Campus Only

Restricted to Campus until

5-15-2025

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