Take, for example, the birds that you are going to study.

They have to build their own houses, and feed their children, and travel about every year on their own particular business." "Travel--do birds travel ?" cried both children in the same breath.

"Oh, where do they go, and what for ?" "Father will tell you about that.

Now you must do what he said--each find a bird, and see if you can describe it.

Suppose we sit on this great root.