Why do females sing? Pair communication and other song functions in eastern bluebirds.

Female bird song has been underappreciated and understudied, especially in temperate species. Birdsong was originally thought to be a trait used primarily by male songbirds for mate attraction and male/male contest. However, ornithologists have long known that females sing in many tropical songbirds, often for similar functions to male song. Yet studies of female song in temperate regions remain scarce. Increasing our understanding of the function of female song in temperate species is a powerful step towards discerning the selective pressures that maintain elaborate female signals. In the last few decades, studies of temperate species have highlighted five major functional categories of female song. Using a modelling framework, based on all known functions of song in other species, we tested the function of female song in eastern bluebirds. The modelling framework allowed us to test the effect of multiple complex behaviors simultaneously to predict female song function. Additionally, m...