“Of course they can.  Ears of all animals are made to hear with.  This Sparrow can hear quite as well as you can, Nat.  Now think, children, how many things we have found about this Sparrow’s head that are quite like our own,—­ears, eyes, nose, mouth, and tongue,—­only there are no lips or teeth, because the horny beak, with its hard edges and sharp point, answers both for lips and teeth.  I want you to learn from this how many things are really alike in Bird People and House People, though they look so different at first sight.  When we come to the bird stories, you will find that birds differ very much among themselves in all these things.  I will show you all sorts of beaks, of different sizes and shapes.  Here are pictures of several kinds of beaks—­see how much they differ in shape!  But they are all beaks, and all beaks are mouths.  They all answer the same purposes in birds’ lives, and the purposes are the same as those of our mouths.  But now, what do you notice about this Sparrow’s feet?”

“They are not a bit like my feet,” said Dodo; “they are so long and slim and hard, and the toes stick out so all around.  I think mine are nicer.”

“But they would not be so useful as this Sparrow’s if you had to live in a bush and hop about on the twigs,” said the Doctor.  “The bird’s feet are fixed as nicely for that, as yours are for walking on the ground.  I can show you, too, little girl, that a Sparrow’s feet are a great deal more like yours than you think.  Come, Rap!  Tell me what you see about this bird’s feet.”

“Why, they are the ends of its legs, and there is a long slim part beyond the feathers, hard and horny like the beak, and at the end of this are four toes, three in front and one behind, and they’ve all sharp claws on their ends.”

“Very well said, my boy!  Now I will show you that such feet as the Sparrow has are as much like Dodo’s as a Sparrow’s beak is like her mouth.  Begin with the claws—­”

[Illustration:  FIG. 1.  Insect-eating bill of Robin; 2.  Seed-crushing bill of a Sparrow; 3.  Snapping bill of Whip-poor-will; 4.  Needle bill of Hummingbird; 5.  Chiselling bill of Woodpecker; 6.  Climbing bill of Paroquet; 7.  Tearing bill of Falcon; 8.  Grooved drinking bill of Dove; 9.  Gleaning bill of Ruffed Grouse; 10.  Wedge bill of Plover; 11.  Straight probing bill of Snipe.]

[Illustration:  FIG 12:  Curved probing bill of Curlew; 13.  Spearing bill of Green Heron; 14.  Strainer bill of Duck; 15.  Hooked bill of Gull; 16.  Ornamental bill of male Puffin in breeding season.]

“I know!” exclaimed Dodo, “toe-nails!  Only I think they need cutting!”