Simulating winning in the wild - The behavioral and hormonal response of black redstarts to single and repeated territorial challenges of high and low intensity

► Free-living male black redstarts were challenged with repeated simulated territorial intrusions of high or low intensity. ► Repeated intrusions had no influence on testosterone and corticosterone levels. ► However, the behavior changed over days depending on the intensity of the intrusion. ► Our data show that it is unlikely that STIs induce a losing experience. ► A hormonal effect of winning an encounter may not be universal in vertebrates.