Training ducklings in broods interferes with maternal imprinting

Under natural conditions, if maternal imprinting is to occur it must occur in a social situation which includes the presence of broodmates. In the laboratory it has been shown that social rearing with siblings prior to maternal imprinting interferes with the establishment of maternal imprinting, whereas social experience with siblings after maternal imprinting enhances the imprinting experience. The present study examined the influence of social experience with broodmates during an imprinting trial on the establishment of a visually imprinted maternal preference in domestic mallard ducklings (Anas platyrhynchos). Twenty-four-hour-old ducklings were allowed to follow a stuffed mallard hen for 30 min either individually or in a brood of four same-aged ducklings. The birds trained alone subsequently showed an imprinted preference for the familiar mallard hen over an unfamiliar pintail hen or four stuffed ducklings in simultaneous choice tests at 48 and 72 hr after hatching. Ducklings trained with broodmates did not show a preference for the familiar mallard hen over the unfamiliar pintail hen and displayed a preference for the stuffed ducklings over the mallard hen at 48 and 72 hr choice tests. These results demonstrate that even brief (30 min) experience with siblings during a maternal imprinting trial results in peer imprinting that interferes with the establishment of maternal imprinting. These and other results of a similar sort render dubious the significance of most laboratory studies of imprinting for an understanding of such events in nature.