Perturbation of social interactions is one of the most efficient stressors in animals. Separation of affiliated individuals provokes behavioural perturbations and stress hormones overshoot. Whereas this aspect of social affiliation has been extensively described between monogamous partners or between mother and young, few studies dealt with potential social bonds between group-mates. In the gregarious zebra finch (Taeniopygia guttata), we recently demonstrated that social isolation of males modifies not only call rate in response to female calls, but also acoustic structure of evoked calls. Here we hypothesize that these modifications in call response are stress-induced and reveal the perturbation by isolation of existing social bonds with group-mates. If so, the experimental increase of plasma corticosterone level of males in normal social context should mimic the effect of social isolation. After oral administration of corticosterone, we measure males’ response to female calls of varied salience (familiar and unfamiliar females) in the presence of a familiar audience. We report that an increase in circulating stress hormone modifies male zebra finches call response to female calls. We propose that modifications of call structure could carry information about the emitter emotional state.