"Those are a pair of Redstarts," she said, "and they are picking up ants.

"You certainly have to remember the laws of Birdland, as well as their exceptions," answered the Doctor; "but when you have once recognized and named a bird you will carry its picture always in your mind, for the Redstarts that you will see when you are very old men and women, will be like the one that is dancing along the walk now.