the birds know it by heart
Because you are stupid
Because the early birds found ways to build nests. Birds know how to build nests so they can survive in this way until today. It is the natural selection.
Some birds do not build nest's .why?
Well birds build nests in them.
in trees
Birds
Three animals other than birds that build nests: wasp, turtle, gorilla.
No birds build nests but goats may scrape out an area in the soil to get to the cooler ground.
Their usually sticks.
Birds build nests to protect their eggs.
eagles or valtures
Places where birds build nests.