The impact of urban centers on American goldfinches (Spinus tristis) overwintering at high latitudes
Date Approved
2016
Degree Type
Open Access Thesis
Degree Name
Master of Science (MS)
Department or School
Biology
Committee Member
Peter Bednekoff, PhD, Chair
Committee Member
Jamie Cornelius, PhD
Committee Member
Katherine Greenwald, PhD
Abstract
American Goldfinches (Spinus tristis) are partial migrants that overwinter in northern regions where winters can be extreme. To understand the role of urban development in facilitating use of a harsh climate, I conducted winter point count surveys (n = 297) at urban and rural sites across latitudes in Michigan. The following winter I trapped individuals in urban and rural settings to sample baseline and stress-induced plasma corticosterone (CORT) levels. Analyses revealed no interaction of latitude and urbanization in the winter distribution of American Goldfinches. Similarly, CORT concentrations did not differ between individuals trapped in urban and rural settings. It does not appear that American Goldfinches preferentially use urban areas in winter, and urban individuals do not exhibit different CORT responses to stressors. Birds captured at sites where feeders were regularly provided did display higher baseline CORT concentrations; birds with higher CORT may be more likely to locate supplemental food.
Recommended Citation
Navis, Corrie Jean, "The impact of urban centers on American goldfinches (Spinus tristis) overwintering at high latitudes" (2016). Master's Theses and Doctoral Dissertations. 908.
https://commons.emich.edu/theses/908