Document Type

Honors Thesis

Major

Ecology & Environmental Sciences, Wildlife Ecology

Advisor(s)

Erik Blomberg

Committee Members

Melissa Ladenheim, Victor Ortega-Jimènez

Graduation Year

May 2024

Publication Date

Spring 5-2024

Abstract

Urban landscapes may influence bird species in complex ways, with some species exploiting urban environments, others adapting to them, and others avoiding them. Migratory birds encounter urbanization not just during breeding and overwintering, but also at stopping sites during migration. Migration routes of American Woodcock (Scolopax minor), a bird species experiencing long term population declines, follow the east coast of the United States, including the major urbanized areas of the eastern seaboard. I explored the effects of urbanization around stopping sites on Woodcock migratory behavior using the percentage of impervious surfaces within a buffer surrounding the site as a measure of urbanization. I used four variables to quantify stopping behavior: stopover duration, average movement distance within stopover, stopping event type (stop or stopover), and subsequent migratory step length. I predicted that greater levels of urbanization would result in less favorable stopping sites, which I hypothesized would be associated with shorter stopping events, a greater likelihood of stops as opposed to stopovers, longer movements within stopovers and a shorter subsequent migratory step length. I used a tiered AICc model selection approach with generalized linear models, while accounting for the potential confounding effects of demographic, spatial, and temporal variables on Woodcock behavior. I found little evidence that impervious surface cover affected Woodcock migratory stopping behavior, which could indicate that urbanization in their migratory range is not a major concern for the species. However, I also noted a low frequency of stopping sites in very urbanized areas and some non-linear patterns in the data, which may suggest a potential threshold effect that could be investigated by further study.

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