Answer:
This is a case of natural selection
Step-by-step explanation:
Mutations are a fundamental part of the process of evolution by natural selection. These are a random genetic modifications that occur on every organism - some are beneficial and others could be harmful or disadvantageous. Therefore, natural selection decides which mutations will stay on a population and which ones will be eliminated.
In this scenario, this mutation enables the male bird to carry out better mating rituals, therefore it would be considered beneficial as it helps the species to reproduce and survive. So, it will be passed on from generation to generation, making other individuals fit for survival.