The Ugly Duckling is a well-known fairy tale by Andersen, which tells a story with a heartbreaking process but a warm ending. One day, a mother duck hatched a special little duck. Because this little duck looked very ugly and different from other ducks, it was often teased and bullied by other ducks. After many humiliations, until the spring of the next year, the ugly duckling saw its own reflection in the water and realized that it had become a beautiful white swan. This story brought comfort to many people who were in misfortune. Is the ugly duckling becoming a white swan just a fairy tale, or is it true? Of course, this is not a completely fictional story. It was the amazing changes in the growth and development of swans from juveniles to adults in the real world that inspired Andersen to write this story.
So, how does this change happen? In addition to physical growth, the biggest change in the development of chicks is the change of feathers. From the sparse brown-gray down feathers of the ugly duckling, it changes to the white, smooth, and dense adult feathers. Of course, the down feathers of chicks don't grow directly into adult feathers. From the chicks' down feathers when they just hatch to beautiful adult feathers, there are many moulting processes. Moulting is the process of shedding old feathers and growing new ones. It is an important biological phenomenon in birds. Even after adulthood, birds still regularly molt every year, usually twice a year. Through moulting, they deal with the wear and tear of feathers in daily activities and meet the needs of mating display, breeding, and migration flying.
The moulting of birds has a fixed pattern and is carried out sequentially. That is to say, all feathers are not replaced at the same time, but in an orderly alternating process. This is similar to the shedding and regeneration of leaves in evergreen plants. Although the appearance of feathers may show some imperfections, it generally does not affect their ability to insulate, protect, and fly. Of course, there are also some birds, such as ducks and swans, that shed their flight feathers at the same time, which results in the loss of their flying ability during this period. At this time, they hide in remote and easy-to-hide lakes and aquatic plants to avoid being detected by predators and survive the difficult period. For swans, this period lasts about 6 weeks.