Figure 3. Phenotypic and physiological measures: Box plot showing 5%–95% intervals of cloacal protuberance volume (a), plasma testosterone (b), body mass (c), and fat score (d) in migrant (hollow box plot) and resident (black box plot) juncos. Student’s t test was used to determine the significance between migrant and resident response, the alpha was set at 0.05. An asterisk (*) indicates a significant difference in parameters compared between migrant and resident juncos.