Effects of nestboxes and males on female song activity in the European starling: an experimental study

Abstract

AbstractEnvironmental, contextual or social factors influencing song in female songbirds have been little studied. Female European starlings Sturnus vulgaris sing robustly throughout most of the year, except during the breeding season when their song production dramatically decreases. Here we experimentally investigated the effect of the presence of males and/or nestboxes on song production in captive female starlings during the breeding season. Spontaneous song activity of two experimental groups and one control group (housed with nestboxes, but no males) was observed for one month from the end of March onwards. Additionally, we tested whether female song rate is related to oestradiol plasma levels. The experimental results showed that song rate significantly decreased with the progressing of the breeding season and this process seemed not to be regulated by oestradiol. Nestboxes clearly promoted song production, as previously found in male starlings, while the presence of males negatively affected female song rate. Taken together these results indicate that, in the course of the breeding period, the suppressive influence of the day length and the presence of males on female song production override the stimulating effect of nestboxes, and that engagement in breeding activities is largely incompatible with singing in female starlings.