Maturation of GABAergic transmission in a songbird motor nucleus

Abstract

In seasonally breeding songbirds, such as European starlings (Sturnus vulgaris), male song plays a direct role in immediate mate attraction during, but not outside of, the breeding season. The present experiment was designed to explore whether female starlings would display differential behavioral responses to male song recorded during (spring) and outside of (fall) the breeding season. Recordings of spring and fall male starling songs were broadcast to female starlings from nest boxes in an aviary setting. Females displayed marked elevations in general activity (landing, eating, and drinking) in response to spring compared to fall song, however as a group females did not preferentially land on nest boxes playing spring song. The volume of the song control nucleus HVC was largest in females that landed more often on nest boxes during playbacks of spring song compared to fall song, and the volume of the lateral portions of the magnocellular nucleus of the anterior neostriatum (lMAN) related positively to the extent to which females directed landings towards nest boxes playing spring rather than fall song. A possible relationship was also detected between female preferences for male spring compared to fall song and the volume of the robust nucleus of the archistriatum. Female responses to spring and fall song did not relate to the volumes of area X, or to estrogen concentrations. These data provide evidence that females attend to and respond behaviorally to seasonal changes in male starling song, and implicate song control nuclei, HVC and lMAN, in female perception and discrimination of male song.