Multimodal signaling systems are shaped not only by a signaler’s physical abilities but also by external factors such as the position of signal receivers and the properties of the medium through which the signals are transmitted. To fully understand the evolution and function of multimodal communication, it is essential to investigate the behavior in the wild. Here, I present evidence that socially monogamous songbirds perform complex courtship displays that can produce multimodal and multicomponent signals in wild conditions. Cordon-bleus (Uraeginthus spp.) are socially monogamous songbirds from East Africa. Both sexes of cordon-bleus perform multimodal courtship displays by holding a piece of nest material, bobbing up and down, and singing. My previous laboratory study using high-speed video cameras revealed that courtship bobbing includes multiple rapid steps similar to human tap-dancing, which presumably contributes to producing non-vocal sounds and/or vibrations in addition to visual signals. As a result of field observation and behavioral analysis, I found that wild cordon-bleus perform tap-dance like displays just as captive cordon-bleus. I also observed that wild cordon-bleus produced non-vocal sounds and shook branches during courtship, which can contribute to multimodal signal production (i.e., visual, acoustic, and vibrational signals). My findings imply that the courtship displays of cordon-bleus are an ideal candidate for investigating the role and function of multimodal communication in animals, and demonstrate the importance of further quantitative studies in both laboratory and field.

中文翻译：

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野外的踢踏舞者：在社会上一夫一妻制的鸣禽中多模式求偶表演的现场观察。

多模式信令系统不仅受信令员的物理能力的影响，而且还受外部因素的影响，例如信号接收器的位置以及通过其传输信号的介质的属性。要充分了解多模式通信的演变和功能，必须调查野外行为。在这里，我提供了证据，证明一夫一妻制的社交鸟会执行复杂的求爱显示，从而在野外条件下产生多模式和多分量信号。警戒线（Uraeginthusspp。）是来自东非的社会一夫一妻制的鸣禽。警戒线的两性都通过拿着一块嵌套材料，上下摆动和唱歌来执行多模式求爱显示。我以前使用高速摄像机进行的实验室研究表明，求爱动摇包括多个快速步骤，类似于人类的踢踏舞，这大概除了产生视觉信号外，还有助于产生非声音的声音和/或振动。现场观察和行为分析的结果是，我发现野生的警戒线失误表现出与显示一样的敲击舞，就像圈养的警戒线失误一样。我还观察到，野生的警戒线在求爱过程中会产生非声音的声音并摇动树枝，这可能有助于产生多模态信号（即视觉，听觉和振动信号）。