Birdsong is a particularly useful model for animal communication studies. However, current knowledge is derived mainly from the study of male song, and is therefore incomplete. Here, we investigated whether singing behaviour differs between sexes in the cooperatively breeding Western Australian magpie (Gymnorhina tibicen dorsalis). This subspecies lives in territorial groups, and in our population there is a female-biased sex ratio, which may lead to a high level of female-female competition for males. Observations of 94 magpies (54 females, 40 males) revealed that females sang more often than males. As bird song is a sexually multidimensional signal, we also studied amplitude and structure of the main territorial high-amplitude song in magpie; the carol. We found that females sing at the same amplitude as males, but that male and female carols exhibit differences in frequency. These results highlight the importance of studying female song and may change our perception regarding the evolution of sex-specific traits, given the primary focus on male singing as a sexually selected trait in the literature to date. The next step is to discover additional species in which females sing more than males in order to improve our currently incomplete understanding of the evolution of bird song.

中文翻译：

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澳大利亚喜鹊的女性唱歌频率高于男性

鸟鸣是动物交流研究的一个特别有用的模型。然而，目前的知识主要来自对男性歌曲的研究，因此是不完整的。在这里，我们调查了合作繁殖的西澳大利亚喜鹊（Gymnorhina tibicen dorsalis）的两性之间的歌唱行为是否不同。该亚种生活在领土群体中，在我们的人口中存在偏向女性的性别比例，这可能导致女性与男性之间的高水平竞争。对 94 只喜鹊（54 只雌性，40 只雄性）的观察表明，雌性比雄性更常唱歌。由于鸟鸣是一种性多维信号，我们还研究了喜鹊主要领地高振幅鸣叫的振幅和结构；颂歌。我们发现女性唱歌的幅度与男性相同，但男性和女性颂歌的频率存在差异。这些结果突出了研究女性歌曲的重要性，并且可能会改变我们对特定性别特征进化的看法，因为迄今为止文献中主要关注男性歌唱作为性选择特征。下一步是发现雌性比雄性唱歌更多的其他物种，以提高我们目前对鸟鸣进化的不完整理解。