The neuroendocrine correlates of song behavior in a finch species with extensive male and female song

Abstract

Birdsong is a relatively well-studied behavior, both due to its importance as a model for vocal production learning and as an intriguing complex social behavior. Until the last few decades work on birdsong focused almost exclusively on males. However, it is now widely accepted that female song not only exists, but is fairly common throughout the oscine passerines. Despite this, and the large number of researchers who have begun exploring female song in the field, researchers in the lab have been slow to adopt model species with female song. Studying female song in the lab is critical for our understanding of sex differences in the physiology controlling this fascinating behavior. Additionally, as a model for vocal production learning in humans, understanding the mechanistic and neuroendocrine control of female song is clearly important. In this study, we report neuroendocrine correlates of female song in the red-cheeked cordon bleu (RCCB), a finch species with extensive female song. Specifically, we focused on characterizing song rate and circulating hormone levels, as well as nuclei volumes and cell densities within the song control system (SCS). Additionally, we report on motor-driven expression of the immediate early gene ZENK in the SCS of male and female RCCBs.