What's wrong with pearl birds without breeding?

The reason why pearl birds do not reproduce is because it has not yet reached a period of reproduction, or there is no preparation of a breeding nest.Its breeding period is spring and summer. At that time, it will find natural cave camp nests. It uses fine grass, feathers, fibers, etc. as materials. Each nest can produce 3-7 eggs.1-5.After spawning, the female birds are responsible for incubation during the day, and the male birds are responsible for guarding, and the incubation takes about 13-20 days.