What purpose do the crests bright wing patches or long plumes on male birds serve?

The bright wing patches and long plumes on male birds primarily serve as visual signals in sexual selection. These features attract females by showcasing the male's health, vitality, and genetic fitness, which can indicate their ability to thrive in their environment. Additionally, they may play a role in territory defense and establishing dominance among males. Overall, these traits enhance reproductive success by making males more appealing to potential mates.