Date of Completion
The purpose of this study was to investigate the proposed idea that certain traits of the saltmarsh sparrow change in appearance over the course of a season. This study also investigated whether such changed differed between sexes. I hypothesized that such changes would prove evident, both over time and between sexes. For this study, saltmarsh sparrows (Ammodramus caudacutus) were captured across five sites in Connecticut during the 2011 and 2012 breeding seasons. The saltmarsh sparrows were captured, had their plumage traits scored according to a protocol developed by Shriver et al. (2005), photographed, and released. I conducted scoring based on photographs viewed on computer in a lab setting, in an attempt to see if there were any significant trends in how the sparrows’ plumage varied over time or between sexes. Poisson regressions and paired t-tests were used to investigate these hypothesized trends in plumage variation. There ultimately appeared to be no evidence to indicate such patterns, although one analysis suggested that crown definition may increase over the course of a season. I also hypothesized that the scores of some traits would correlate highly with the scores of others, which could allow a simplification of the scoring protocol in which fewer traits need to be scored without any substantial information about the bird being lost. However, no traits correlated with each other to a particularly high degree.
Minalga, Alex J., "Plumage variation in the saltmarsh sparrow" (2015). Honors Scholar Theses. 410.