DEVELOPMENT OF PRENATAL ACOUSTIC INTERACTION IN THE MUSCOVY DUCK (CAIRINA-MOSCHATA)

1. The development of prenatal acoustic communication was investigated in Muscovy ducks, comparing the vocalisation activities and call types in isolated eggs and pairs of embryos (two eggs in shell contact). 2. Incubator experiments showed that the number of vocalisations in embryos which had mutual acoustic contact was nearly twice that of isolated ones. 3. An acoustic interaction, that is, an exchange of signals, was only recognised after the first chick had hatched, that is, between embryos and chicks. 4. Specific call types used for communication were the double call and the trill call.