How long does Gray Birds be born until flying?

The gray bird can fly in less than a month after birth.This bird is born in half a year, but it can not be reproduced after eight months.It usually built the nest in the shrub or small trees, and it can breed after the nest is built.Every year, 4 nests can be reproduced. There are 4-7 eggs per nest. Usually it will only be incubated for 16-18 days to get out of the shell. It will open your eyes for 10 days.Generally, 45 days will leave the mother bird.