Fig. 3From: Neuroendocrine patterns underlying seasonal song and year-round territoriality in male black redstartsMean estimates ± 95% CI and individual data points of testis volume and testosterone concentrations across seasons. Testes (a) were larger during breeding (N = 7) compared to molt (N = 5) and nonbreeding (N = 6; p < 0.001). Plasma levels of testosterone (b) were higher during breeding than during molt and nonbreeding (p = 0.01)Back to article page