Animal communication networks: social, environmental, and anthropogenic drivers of behaviour

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鸣禽日间鸣叫行为的研究。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。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）对黎明合唱和夜间合唱的影响尚不清楚。然而，这两种信号在决定健康方面的作用至少与白天的信号一样重要。我和我的学生将要进行的研究是为了验证为什么鸟类在这些环境中唱歌的假设。本文采用观察与实验相结合的方法和多种假设检验来评估三种鸣禽（黑顶山雀、白喉麻雀和烤鸟）声音表现的影响因素。我们专注于语音信号在通信网络的背景下（其中多个信号和接收器同时交换信息）。为此，我们使用强大的新录音和歌曲回放技术来记录领土所有者的网络，这样影响展示的社会环境和非生物因素就可以同时考虑。通过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，并研究网络的涌现特性。除了了解这些声音显示如何在自然条件下发挥作用外，我还提出了实验来测试声音显示如何受到光和噪音的影响。人们越来越了解人为的噪音和光线可以改变野生动物种群的行为和适应性。然而，这些特征在景观中的共存模式或它们对领土所有者定居模式的影响使许多研究感到困惑。我提出的实验将包括在一个未受干扰的自然种群中使用滑雪道单独或共同控制噪音和光线水平。结合对黎明和夜间歌声的观察和实验研究，实验操作将提供对动物在景观中面临的日益增加的人为压力的生态影响的见解。了解动物如何交流以及不同的表现如何影响自然系统的适应性是必要的。此外，从长远来看，了解改变系统如何影响动物的行为和生态，可以为保护和减轻损害的战略提供信息。

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 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. The social (e.g. territory boundaries, relative quality of neighbours) and environmental (e.g. weather, ambient light) factors influencing both the dawn chorus and nocturnal singing are not well understood. However, both displays likely play at least equally important roles as daytime signalling does in determining fitness. The studies that my students and I will conduct are designed to test hypotheses for why birds sing in these contexts. We use a combined observational and experimental approach and multiple hypotheses testing to assess the factors influencing vocal displays in three songbird species: black-capped chickadees, white-throated sparrows, and ovenbirds. We focus on vocal signalling in the context of communication networks (where multiple signallers and receivers exchanging information simultaneously). To do so, we use powerful new recording and song playback techniques to record networks of territory holders, such that the social environment and the abiotic factors that influence displays can be considered in concert. By analyzing vocal behaviours in this way, we can provide new insights into animal communication and study emergent properties of networks. In addition to understanding how these vocal displays function in natural conditions, I propose experiments to test how vocal displays are influenced by light and noise. Anthropogenic noise and light are increasingly understood to alter behaviour and fitness of wild-animal populations. However, many studies are confounded by the co-occurrence patterns of these features in the landscape or their influence on settlement patterns of territory holders. The experiments I propose will involve manipulating noise and light levels independently and together using a ski-trail in an otherwise undisturbed natural population. Together with the observational and experimental studies of dawn and nocturnal song, the experimental manipulation will provide insight into ecological effects of the increasing anthropogenic pressures animals face in the landscape. It is imperative to understand how animals communicate and how different displays influence fitness in natural systems. In addition, insights into how altering the system can influence behaviour and ecology of animals can inform conservation and damage mitigation strategies in the longer term.