Response-contigent prenatal experience of maternal calls in the Peking duck (Anas platyrhynchos)

As the time of hatching approaches, an incubating bird often vocalizes in apparent response to the movements and calls of the embryos beneath. An experiment was designed to see whether Peking duck embryos, exposed to (mallard or chicken) maternal calls presented to them in response to their foot-movements (as indicator of their motor-activity) on the day before hatching, differed in their responsiveness from other embryos exposed to the same calls but not contingent upon their own movements. The results show that response rate was significantly increased to the mallard maternal call, but not to the chiken maternal call, as a function of the contingency.