Birdsong Acquisition Model by Sexual Selection Focused on the Habitat Density

Abstract

We describe a simulation model based on an avian ecosystem for determining what causes birdsong evolution. It is already known that songbirds communicate with a “birdsong.” This birdsong is used in territorial and courtship behaviors. Some previous researches have suggested that songs related to territorial behaviors should have simple structures while those related to courtship behaviors should have complex ones. We suspect that birdsongs are constantly evolving to achieve a suitable balance between the two behaviors while considering the surrounding environment. We consider avian habitat density to be one of the most important environmental factors influencing birdsong evolution and therefore created different densities in a simulation model. In this paper, we propose a birdsong acquisition model by sexual selection that contains both territorial and courtship behaviors. We conducted simulations with the proposed model and determined that the evolution of birdsongs differs depending on a bird's habitat density. The experimental results suggest that a bird's habitat density influences the structure of birdsongs, as well.