Soziale Verhaltensweisen bei hörenden und gehörlosen Dompfaffen (Pyrrhula pyrrhula L.)

Summary

The behaviour of bullfinches (Pyrrhula) after removal of the cochlea is studied. The influence of acoustical and optical stimuli upon the social contacts is compared. Parts of the social behaviour are controlled mainly acoustically, e.g. the attraction of a single bird by a calling fellow. Also the final raising of young birds is not possible without acoustical contacts between parents and offspring. The formation of pairs, however, nest-building, laying of fertilized eggs, and breeding are performed normally by birds without hearing. Also the social order within a group of bullfinches regulates itself without acoustical perception by its members. The alarming behaviour seems to be transferred within a group by optical signals.