Jatin - Jasola Village Jasola New Delhi Delhi

From the past 4 Days, I have seen 3 sparrows in my balcony.
My room is on the second floor. I do not use my balcony at all.
It is all dirty in dust and I have not cleaned it from the past 3-4 weeks or may be more.
Now, I have come across that daily 3-4 sparrows come into my balcony and pick out pricks,straws and feathers and then they fly away.
I think they are building a nest somewhere,but I am unable to trace the location of their nest.
I have also clicked some photos of them while they were in my balcony.
That was such a lovely scene.
I am very happy that sparrows are visiting my balcony.