Song and plumage effects on aggressive display by the European Robin Erithacus rubecula

The response was observed of territory‐holding male European Robins ETithacus rubecula to red— and brown‐breasted model Robins which were presented either simultaneously with tape‐recorded Robin song, or with no song. Robins displayed and sang at the silent red‐breasted model, but sang and displayed much more at the models that were presented with song. It is suggested that, while the red breast is one important feature of Robins eliciting aggressive behaviour, song is also important. The relationship of these findings to studies of stimulus features eliciting behaviour in other species is discussed.