Maternal influences on vocal development in a precocial bird, the Japanese Quail (Coturnix c. japonica)
Résumé
In many mammals and birds, the mother play a major role in the development of their young through pre- and postnatal influences. As early as prenatally, the embryo is exposed to olfactory, visual and auditory stimulations that are likely to affect the behavioural expression of the young during postnatal life. In particular, several studies have shown the effects of auditory stimulation in ovo on perceptual responses or hearing preferences for maternal vocalizations after hatching. The mother can also influence the behavioural phenotype of her young at the postnatal stage through her presence and behaviour. In this study, we explored both prenatal and postnatal maternal influences on the vocal development of a precocial bird, the Japanese quail (Coturnix c. japonica). To do this, fertilized eggs were incubated in the laboratory, and they were stimulated (s) or not (ns) by maternal vocalizations during the last days of incubation. After hatching, the stimulated group and the control groups were paired, and were raised with (M) or without an adoptive mother (NM). The vocal development of chicks from four experimental groups were thus compared: Ms, Mns, NMs and NMns. Vocalizations were recorded in situation of social isolation (separation from the familiar chick (all groups) and from the mother (Ms and Mns), during the mothering period and until the age of two months. The first results indicate pre- and postnatal maternal influences on vocalizations’ structure. This confirms that vocal plasticity exists in the Japanese quail, a species that is traditionally considered as a non-vocal learner.