How does the sparrow build a nest

Sparrows are generally built in human houses, and some will be built in the tree cave, and some will seize the nest of the swallow.This bird's nest is relatively simple, and it is usually paved with dry grass, wool, feathers, etc.The nest is generally used to breed. It can produce two nests every year. There are 4-6 eggs per nest. Usually, it can be hatched in 11-12 days. Young birds need to fly after half a month to fly for food.