Date of Defense


Date of Graduation



Biological Sciences

First Advisor

Maarten Vonhof

Second Advisor

Sharon Gill


Urbanization leads to biodiversity loss and exposes animals to environmental challenges that they would not have previously experienced. Increasing evidence has shown that relatively few species can adapt to the rapid growth of urbanization; our world is quickly becoming more urbanized. In the United States, we see the vast majority of the human population living in urban and suburban areas. With urbanization, we see an evolving landscape that eliminates natural land and changes many habitats for the growing human population. What we need to ask ourselves is, how do these changes affect the animal populations? Urbanized habitats can be beneficial to populations due to the decrease in climate stress and more predictable sources of food. However, environmental changes associated with urbanization, such as noise, air/water pollution, habitat/climate modifications, and altered communities of competitors may result in increased overall physiological stress and a decline in reproductive success (fitness) of urban populations. Here we will quantify the amount of stress experienced by four species of wild songbirds, the Northern Cardinal (Cardinalis cardinalis), White-breasted Nuthatch (Sitta carolinensis), Tufted Titmouse (Baeolophus bicolor) and Black-capped Chickadee (Poecile atricapillus), across an urbanization gradient. In this study, we have collected blood samples from the four bird species located in both rural and urban habitats to determine the heterophil:lymphocyte (H/L) ratios. Using the H/L ratios, we were able to determine the stress of each individual. We found that there was no significant difference between the H/L ratios of the urban or rural populations for any of the four target species. The four species did not show a change in body condition due to urbanization.

Access Setting

Honors Thesis-Restricted