Ontogeny of calls of a nonpasserine species:: the grey crowned crane Balearica regulorum gibbericeps

This study presents the results of preliminary studies on the ontogeny of two of the three calls of chicks of the grey crowned crane Balearica regulorum gibbericeps. The observed patterns are consistent with those presented in other studies of nonpasserine bird species in that the frequency range decreased in both investigated calls. The duration, however, showed fluctuations in the contact call and no consistent pattern. In the begging call of captive chicks the duration increased as is found in other nonpasserine bird species.