Behaviour 2019
Female song is acoustically similar to male song in Orchard Orioles
Michelle J Moyer, Kevin E. Omland, D'Juan A. Moreland, Aiman Raza, Bernard S. Lohr. University of Maryland, Baltimore County, Baltimore, MD, United States

Female birds in many temperate species are thought to sing reduced or quieter songs and appear to sing less often than their male counterparts. Increasingly, researchers are recording female song in well-studied species in which females were generally not thought to sing. Here we document extensive use of female song in Orchard Orioles (Icterus spurius), a species previously assumed to have little or no female song. We performed acoustic analyses comparing male and female song structure, and investigated the song rates of each sex. Though females sang significantly less often than males, female and male songs were statistically equivalent for five of the seven variables investigated, indicating that the two sexes sing acoustically similar songs. Females also sang more often than initially assumed, suggesting that researchers may be missing female song in other species if they are not searching for it, such as in species with delayed plumage maturation (female-like yearling plumage). We are currently conducting song playback experiments to investigate if and how female song may function in this species. Overall, this study highlights the need to re-explore well-studied systems.