Osteological examinations on the budgerigar (Melopsittacus undulatus Shaw 1805) with special reference to skeletal alterations conditioned by breeding.

The aims of this study were to examine the skeleton of domesticated budgerigars of phenotypically different breeding types, to describe the expression of skeletal changes and to discuss the results with special reference to the causes and effects of breed-conditioned alterations. Complete skeletons of 39 adult budgerigars of both sexes were the object of our research. The examinations demonstrated that almost all metrically sized skeleton dimensions of budgerigars of the exhibition type were increased significantly, compared with those of the non-exhibition type. Only for the scapula significant length differences between the budgerigars of both breeding types could not be verified. It can be stated that the measuring parameters 'occipital width', 'maxilla length', 'skull length' and 'prefrontal width' are suitable for the characterization of exhibition budgerigars. However, sexual dimorphisms could be verified in only three parameters (width of the pars symphysialis mandibulae, height of the skull, width of the skull within the range of the occiput). It has to be clarified in future studies to what extent the changes in the skeleton of budgerigars of the exhibition type have already had consequences for their flying ability, metabolism, health and well-being.