Effects of deafening on the development of nestling and juvenile vocalizations in budgerigars (Melopsittacus undulatus)

The effects of complete and partial cochlear extirpation at ages 9-11 days posthatch were assessed in 5 nestling budgerigars (Melopsittacus undulatus) to determine if auditory feedback is necessary for the production of nestl ing vocalizations. Although early deafening had no effect on the production of food-begging calls produced during the first 2 weeks posthatch, deafeni ng did disrupt the expected transition from these early calls to the longer and more complex frequency-modulated, patterned food-begging calls normall y appearing 3-4 weeks posthatch. All birds sustaining either complete or pa rtial cochlear extirpation failed to develop stereotyped contact calls arou nd the time of hedging at 5 weeks. These results are consistent with previo us research showing that deafened nestlings do not develop normal contact c alls (R. J. Dooling, B. F Gephart, P H. Price, C. McHale, & S, E. Brauth, 1 987) and also indicate that a form of sensorimotor learning is involved in the production of mature, patterned food-begging calls in budgerigars.