Data for: Birdsong as an indicator of habitat structure and quality

Birdsong is a complex and highly flexible sexual signal that plays a crucial role in intra- and intersexual communication. Various aspects of the surrounding habitat can influence birdsong, for example, birds may modify their songs to enhance acoustic transmission, or males in high-quality territories with abundant food resources may produce more elaborated songs. However, these mechanisms remain largely unexplored in many natural systems. In our field study, we recorded the songs of male collared flycatchers (<i>Ficedula albicollis</i>) in a Hungarian population, alongside detailed habitat variables reflecting structure and quality. We analysed song traits describing frequency, temporal structure, and complexity. Habitat variables included canopy closure, Shannon diversity index of the tree species, mean trunk circumference of dominant tree species, and tree health status. We revealed that mean song frequency was negatively associated with canopy closure. This result likely reflects birds adjusting the frequency of their songs to the acoustic properties of their environment, or it may be explained by quality-dependent territory selection or the use of high-performance songs to signal territory quality. Our results have implications on the study of sexual selection and how birds adapt to different environments, and suggest that aspects of bird song can reflect habitat quality.

鸟鸣是一种复杂且高度灵活的性信号，在性内与性间交流中发挥着至关重要的作用。周边生境的诸多特征均可对鸟鸣产生影响：例如，鸟类可调整鸣唱以提升声学传播效果；而坐拥食物资源充沛的优质领地的雄鸟，往往能唱出更为精巧繁复的鸣曲。然而，在多数自然种群中，这类影响机制仍未得到充分探索。在本次野外研究中，我们记录了匈牙利种群中雄性白领姬鹟（*Ficedula albicollis*）的鸣唱，同时采集了反映生境结构与质量的详细生境变量数据。我们分析了反映鸣唱频率、时间结构与复杂度的多项鸣唱特征；生境变量则包括林冠郁闭度、树木物种香农多样性指数、优势树种平均胸径以及树木健康状况。研究结果显示，平均鸣唱频率与林冠郁闭度呈负相关。这一结果可能源于鸟类根据生境声学特性调整鸣唱频率，也可能与基于质量的领地选择有关，或是雄鸟通过高质量鸣唱彰显领地品质。本研究结果对性选择研究以及鸟类对不同生境的适应机制探索具有参考价值，同时表明鸟鸣的相关特征可反映生境质量。