Function and repeatability of conspicuous and rare vocal signals

沟通在调节动物的社会和交配行为中起着至关重要的作用。我们对鸟类声音交流的生态学和进化的理解大多来自于对雄性鸣禽白天鸣叫行为的研究。然而，白天活跃的物种经常在太阳升起之前强烈地歌唱，这是一种令人印象深刻的表演，被称为黎明合唱。一些白天唱歌的物种也在晚上唱歌。此外，许多鸣禽物种的雌性也会唱歌，尽管这种行为在大多数物种中还没有得到很好的研究。社会因素（如领土边界、邻居的相对质量）和环境因素（如天气、环境光线、噪音）导致了黎明合唱、夜间歌唱和女性歌唱，这些因素还没有得到很好的理解。然而，这些表现可能至少与白天的信号在决定适应性方面发挥同等重要的作用（通过它们对决定繁殖成功率的贡献）。我和我的学生设计的研究测试了为什么鸟类在这些环境中唱歌的假设。我们采用观察和实验相结合的方法来评估两种鸣禽物种：白喉麻雀和烤鸟的声音显示的影响因素。我们专注于在通信网络（许多人同时通信）的背景下唱歌。为了做到这一点，我们使用强大的新录音和歌曲回放技术来记录整个地区的领土鸟类。这使我们能够研究社会环境和非生物因素如何同时影响表现。使用这种方法，我们还可以评估这些声音显示的可重复性，这对于了解鸟类如何利用它们来评估配偶和竞争对手非常重要。声音显示越一致，就越能更好地传达个人品质的信息。通过这种方式分析声音行为，我们可以为动物交流提供新的见解。了解动物如何交流以及不同的表现如何影响自然系统中的适应性是至关重要的，特别是随着环境变化的加速（例如气候、人类发展带来的噪音和光污染的增加），这些变化可能影响动物的社会行为，包括声音表现。

Communication plays a vital role in mediating the social and mating behaviour of animals. Most of our understanding of the ecology and evolution of vocal communication in birds comes from studies of daytime singing behaviour of male songbirds. However, species that are diurnally active often sing intensely just before the sun rises each day in an impressive display known as the dawn chorus. A number of daytime singing species also sing at night. Additionally, females of many songbird species sing, though this behaviour has not been well studied in most species. The social (e.g. territory boundaries, relative quality of neighbours) and environmental (e.g. weather, ambient light, noise) factors that result in the dawn chorus, nocturnal singing, and female song are not well understood. However, these displays likely play at least equally important roles as daytime signalling does in determining fitness (through their contributions to determining reproductive success). The studies that my students and I have designed test hypotheses for why birds sing in these contexts. We use a combined observational and experimental approaches to assess the factors influencing vocal displays in two songbird species: white-throated sparrows and ovenbirds. We focus on singing in the context of communication networks (where many individuals are communicating simultaneously). To do so, we use powerful new recording and song playback techniques to record entire neighbourhoods of territorial birds. This allows us to examine how the social environment and abiotic factors influence displays simultaneously. Using this approach, we can also assess how repeatable these vocal displays are, which is important for understanding how birds might use them to assess mates and rivals. The more consistently produced a vocal display is, the better it can convey information about individual quality. By analyzing vocal behaviours in this way, we can provide new insights into animal communication. It is essential to understand how animals communicate and how different displays influence fitness in natural systems, particularly with accelerating environmental change (e.g. climate, increases in noise and light pollution from human development) that can influence social behaviours of animals, including vocal displays.