Is the song of Black Redstart males an honest signal of status?

We analyzed song differences between adults and subadults of the Black Redstart (Phoenicurus ochruros) breeding in the Western Alps and found differences both among individuals and between the two age categories. The song parameters utilized for differentiation of individuals were different from those used for adults and subadults. A playback experiment simulating territory intrusion revealed that adults reacted more quickly to the broadcast of an adult song, whereas the reverse was found for subadults. Females did not react to the playback. The results of this study do not support the hypothesis that subadult males mimic female or juvenile behavior (Female or Juvenile Mimicry Hypothesis) nor the Nonadaptive Hypothesis which predicts an equal response to adult and subadult intrusions. We suggest that subadult Black Redstarts honestly signal their status with both visual and acoustic cues. The Status Signaling and the Polyterritorial Deception Hypotheses both seem to explain the data collected for this species.