In the animal kingdom, much like in the world of humans, there are many techniques that animals will use in order to attract mates. Parrots, for example, have glowing heads.
Most birds you see standing on only one leg are doing an impressive balancing act while tucking the second leg into their feathers. This is much easier to recognize in large birds, such as flamingos, but the behavior itself is common to most birds.
The large ones we see when a bird stretches its wings are “flight feathers,” but they also have fluffy ones called “down feathers.”