Little sparrows can only eat insects.

It is very hard for big sparrows to feed little sparrows, because a couple of sparrows need to feed about four children, so how tired they are.

And when little sparrows were young, they could only eat half the food digested by their parents.

that is, the big sparrow eats, digests some, flies back and spits it out to feed the little sparrow.

to protect your children is to teach them to fly.