First Advisor

Benedict, Lauryn

Document Type


Date Created



College of Natural and Health Sciences, Biological Sciences, Biological Sciences Student Work


Anthropogenic activities are drastically and rapidly altering ecosystems. Research has found that urban environments support less biodiversity than non-urban environments. This work has inspired recent interest investigating animal behavior and individual reproductive success in urban wildlife as mechanisms to why biodiversity is lower in urban areas. For my dissertation research, I used three key urban characteristics; noise, light, and landscape composition to study the effects of urbanization on avian species across Weld County, CO. I used these measurements to test the overarching hypothesis that urban land characteristics alter avian community structure and more specific hypotheses regarding how each factor (noise, light, or landscape composition) might contribute to individual reproduction and singing behaviors differently in biologically meaningful ways. My focal study species is the American Robin (Turdus migratorius), a bird species common across many habitat types. In Chapter II, I found that landscape composition has a much stronger effect on avian community composition than noise or light. In chapters II and IV, I use measured song characteristics and reproductive success of individual birds to test for the effects of “urbanness”. I hypothesize that all three urban characteristics would have negative impacts on reproductive output measures, but that urban land characteristics and increased noise would have the main effects on song characteristics. Contrary to my hypothesis, none of the urban characteristics measured had an affect on American Robin reproductive output. In fact, most nests had high survival, large clutch sizes, large brood sizes, and high hatching success. iv Only minimum song frequency was affected by urbanization and more specifically only be percent developed land. Noise and light did not alter song characteristics. Considering the staggering decline of nearly three billion birds in North America since the 1970’s, it is critical that we investigate how anthropogenic changes to habitats may affect wildlife and how wildlife are reacting to these changes. In this dissertation, I discuss the results of this research, the implications of my work, and the importance of connecting the public to the ecosystems in which we all inhabit.


120 pages

Local Identifiers


Rights Statement

Copyright is held by the author.