Fig. 2

Song and syllable diversity metrics in male and female canaries that were treated with Silastic™ implants filled with testosterone (T; gray bars) or with testosterone plus estradiol (T+E2; white bars). Bar graphs represent the mean ± SEM of results that are the average of the first 30 songs produced by each experimental individual after 6 weeks of steroids treatment. Individual data points are also indicated. Data were analyzed by two-way ANOVA with treatment (Trt) and Sex of the subjects as independent factors and results are summarized in the inset for each panel (***p < 0.001, **p < 0.01, *p < 0.05, ns = not significant). The insets have a gray background when showing a sex difference and a white background when no such difference is present. The other inset in panel A indicates the code for the two experimental groups. See Table 1 for the detail of statistical results