Supplementary data from: High-speed infrared video analysis of sonations in the Scissor-tailed Nightjar (<em>Hydropsalis torquata</em>)

Many species of nightjar reportedly produce short, impulsive wing sounds during courtship, but the kinematics and physical mechanisms of sound production remain speculative. Using synchronized infrared high-speed video and audio recordings, we describe the mechanism of sound production of a sonation in the nocturnal family Caprimulgidae; the wing-snapping of male Scissor-tailed Nightjars (Hydropsalis torquata). This sound is a short, sharp, loud, 'tk', produced singly in a jump display (jump snap), in a syncopated series during a flight display (flying snaps), and in a fast series during copulation (copulation snaps). To produce these 'tk' sounds, males rapidly elevated and pronated the wings to slam opposing wrists together. The videos falsify the hypotheses that sound is produced by intra- or inter-wing colliding feathers or by clapping (i.e., a pulse of air accelerating to escape a constricted space, as in human hand-clapping), as there was no contact by the surface of opposing wing-..., , # Supplementary data from: High-speed infrared video analysis of sonations in the Scissor-tailed Nightjar (*Hydropsalis torquata*) Dataset DOI: [10.5061/dryad.4b8gthttj](https://doi.org/10.5061/dryad.4b8gthttj) ## Description of the data and file structure Hydropsalis_torquata_-_Dryad_raw_material.pdf Links to high-speed and normal-speed videos, and to uncompressed sound files of mechanical sounds of *Hydropsalis torquata* , ,据报道，诸多夜鹰（nightjar）物种在求偶阶段会产生短促且富有冲击力的翼部发声，但其发声的运动学（kinematics）与物理机制仍属推测范畴。本研究通过同步红外高速视频与音频录制，阐释了夜行性鸟类类群夜鹰科（Caprimulgidae）中一种发声行为（sonation）的产生机制——雄性剪尾夜鹰（Scissor-tailed Nightjar，*Hydropsalis torquata*）的翼部叩击发声。该鸣响为短促、尖锐且洪亮的“tk”声，可在三种场景下产生：跳跃展示中单次发出（跳跃叩击）、飞行展示中以切分音序列形式发出（飞行叩击），以及交配过程中以快速序列形式发出（交配叩击）。雄性个体通过快速抬升并旋前双翼，使双侧腕部相互撞击以产生此类“tk”声。研究视频证伪了两种既往假说：一是鸣响由翅内或翅间羽毛碰撞产生，二是由拍击发声（即如同人类拍手般，空气在受限空间内加速逸出产生脉冲声波），因双侧翼面并未发生接触…… # 补充数据来源：剪尾夜鹰（*Hydropsalis torquata*）发声行为的高速红外视频分析 数据集DOI：[10.5061/dryad.4b8gthttj]("https://doi.org/10.5061/dryad.4b8gthttj") 数据与文件结构说明 Hydropsalis_torquata_-_Dryad_raw_material.pdf：包含高速与常速视频链接，以及剪尾夜鹰机械鸣响的未压缩音频文件链接