The effect of new recruits on the flock specific call of budgerigars (Melopsittacus undulatus)

A new individual with a different social call was introduced into each of three flocks of three male budgerigars in which the birds were well-established and shared their call. The calls were monitored over the ensuing 53 days and compared using cross-correlational analyses based on the SIGNAL software system. In all cases the call of the new bird changed to conform to that of the group without marked changes in the calls of others. The major change took place approximately 15-30 days after introduction of the new bird. It is suggested that social relations determine the changes that occur in the calls of budgerigars in groups.