Data from: Female song is widespread and ancestral in songbirds

Bird song has historically been considered an almost exclusively male trait, an observation fundamental to the formulation of Darwin’s theory of sexual selection. Like other male ornaments, song is used by male songbirds to attract females and compete with rivals. Thus, bird song has become a textbook example of the power of sexual selection to lead to extreme neurological and behavioural sex differences. Here we present an extensive survey and ancestral state reconstruction of female song across songbirds showing that female song is present in 71% of surveyed species including 32 families, and that females sang in the common ancestor of modern songbirds. Our results reverse classical assumptions about the evolution of song and sex differences in birds. The challenge now is to identify whether sexual selection alone or broader processes, such as social or natural selection, best explain the evolution of elaborate traits in both sexes.长久以来，鸟类鸣唱几乎被认为是雄性独有的特征，这一观察结果是达尔文性选择（sexual selection）理论构建的核心基础。与其他雄性装饰性特征相仿，鸣禽的鸣唱用于吸引雌性个体，并与同类竞争者展开角逐。由此，鸟类鸣唱已成为性选择可催生极端神经与行为性别差异的教科书级范例。本研究针对鸣禽的雌性鸣唱开展了大规模系统性调查与祖先状态重建（ancestral state reconstruction），结果表明：71%的被调查物种存在雌性鸣唱行为，涵盖32个科；且现代鸣禽的共同祖先已具备雌性鸣唱能力。本研究结果推翻了学界关于鸟类鸣唱演化与性别差异的经典假设，当前亟需厘清的核心问题是：究竟仅靠性选择，还是诸如社会选择或自然选择等更广泛的演化过程，能够最恰当地解释两性间复杂精细特征的演化。