During the breeding season of birds, we can see them rushing around to find materials to build nests for laying eggs, incubation, and raising chicks. Therefore, we naturally assume that bird nests are long-term fixed habitats for birds, and that birds must also sleep and rest in their nests at night. In fact, this idea is wrong.
In reality, bird nests are not the lifelong homes of birds. Nests are just "delivery rooms" used by birds to raise their offspring. Generally, after mating, female and male birds will build nests together. Then, the female bird lays eggs and incubates them in the nest. After the chicks hatch, the nest becomes a place for the parents to feed their chicks. As the chicks grow and learn to fly away from the nest and start living on their own, the nest is abandoned. Of course, some birds will reuse old nests when they breed again the following year. Similarly, birds do not use nests as places to sleep and rest at night during the non-breeding season. Most birds rest on tree branches at night; geese and ducks sleep by tucking their heads between their wings and floating directly on the water's surface.