Date of Defense

4-19-2017

Date of Graduation

4-2017

Department

Biological Sciences

First Advisor

Sharon Gill

Second Advisor

Maarten Vonhof

Abstract

Every morning, male songbirds wake from sleeping and begin their daily activities, one of which is to sing. Male songbirds sing to advertise themselves and their territories, making singing a critical feature of breeding and fitness. Many factors could influence when songbirds start to sing to one another, including their breeding stage, the behavior of males around them, and daily weather, especially temperature. But recent changes in environments caused by human, such as increased noise and light pollution could also affect when birds start to sing each day. Urban noise may mask or overlap bird song, and so males may alter timing of singing in order facilitate communication. Light pollution, at night, can cause a change of the onset of daily activity in species that use light to time the beginning their day. I conducted an observation study to measure light and noise pollution around nest boxes of house wrens (Troglodytes aedon), and determine whether these or other factors, such as pairing status, induce house wrens to alter the timing of the first song of their day. On average, males first sang approximately 30 min after sunrise. Analysis of male song during the first month of the breeding season found that timing of the first song was not related to night-time sky brightness or sound pressure levels measured between 0-2 kHz. Instead of noise and light pollution, pairing status influenced when males began to sing, with paired males singing earlier than unpaired birds. Unlike species that sing prior to sunrise, the results suggest that instead of noise and light pollution affecting when males began to sing, social factors, particularly pairing status, had stronger effect. My study helps us understand how urbanization, specifically human-generated light and noise associated with land-use change, affects the environments in which these animals live, and to establish a way to help preserve these natural areas from disruptions cause by humans.

Access Setting

Honors Thesis-Restricted

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