Chapter 6 – Singing in the wild: The ecology of birdsong

Publisher Summary This chapter focuses on the habitat as a source of selection pressures on sound signals. Despite its advantages for communication over long distances and in low-visibility habitats, sound transmission from sender to receiver in natural environments is by no means without problems. Sound attenuates and degrades with distance, in particular when there are obstacles in the landscape that hinder penetration. Turbulence in the air, because of wind or temperature gradients, causes irregular amplitude fluctuations that may distort a song. Many reflective surfaces, such as trunks, branches, leaves, and water and ground surfaces cause echoes that may interfere with signal perception. Furthermore, in a perfect world, there would be no other sounds to confuse the receiver, but in real life the air is full of sounds day and night, produced by neighboring birds and other animals, and by abiotic factors such as wind or rain. Ambient noise in the background interferes with signal detection and recognition. Thus, in dealing with the ecology of birdsong, one has to consider how sound changes when radiating from sender to receiver as a function of habitat characteristics, and to what extent sound perception is affected by ambient noise that varies with habitat and the animals that live there.