Who Taught?

Wooing and making mate, 

Then working hard to make a nest, 

Picking one grass, one twig every time, 

One thread, one wool, one feather, 

Day by day collecting consistently, 

Material for making their nests, 

They distribute their work without, 

Saying a word to each other, 

Female lays eggs in the cosy nest, 

Give sittings one by one to hatch them, 

Then one fine day little ones come out of eggshells, 

Now they nurture them, feed them to grow, 

Again every responsibility is being 

Done with utmost sincerity without 

Any communication, amazingly,

Who taught all these things to these birds?