Function and repeatability of conspicuous and rare vocal signals

交流在调节动物的社会和交配行为方面起着至关重要的作用。我们对鸟类发声交流的生态学和进化的大部分了解来自于对雄性鸣禽白天鸣叫行为的研究。然而，昼夜活动的物种经常在每天太阳升起前激烈歌唱，这是一种令人印象深刻的表演，被称为黎明合唱。一些白天歌唱的物种也在晚上歌唱。此外，许多鸣禽物种的雌性鸣禽会唱歌，尽管在大多数物种中还没有对这种行为进行很好的研究。导致黎明合唱、夜间歌唱和女性歌唱的社会因素(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)还没有被很好地理解。然而，这些信号在确定适合度方面可能至少与白天的信号一样重要(通过它们对决定繁殖成功的贡献)。我和我的学生们设计了一些测试假设，来解释为什么鸟类会在这些环境中歌唱。我们使用观察和实验相结合的方法来评估影响两种鸣禽的发声表现的因素：白喉麻雀和燕雀。我们专注于在交流网络(许多人同时进行交流)的背景下唱歌。为此，我们使用强大的新录音和歌曲回放技术来记录整个区域鸟类的邻里关系。这使我们能够研究社会环境和非生物因素如何同时影响展示。使用这种方法，我们还可以评估这些声音显示的可重复性，这对于了解鸟类可能如何使用它们来评估配偶和竞争对手非常重要。声音显示的效果越稳定，就越能更好地传达有关个人素质的信息。通过以这种方式分析发声行为，我们可以为动物交流提供新的见解。必须了解动物如何交流，以及不同的显示如何影响自然系统的健康，特别是在环境变化加速的情况下(例如，气候、人类发展带来的噪音和光污染的增加)，这可能会影响动物的社会行为，包括发声显示。

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.