"I wonder if we can guess it." "You may all try," said the Doctor.

"It is a bird that every one loves--the home bird who is so fond of House People that whenever we see one, we know that there is a house not far away." "Then it must be the Bluebird!" cried Rap.
"You are right," said the Doctor; "and if you will come here by the window you can watch a pair who are flying in and out of the bird house, on top of the woodshed.

Do you hear?
Bluebirds have a call-note and a sweet warbling song.

As I have told you before, all birds have some note or sound that they use to attract attention or call their mates; but it is only those whose voices are so highly developed that they can make really continuous musical sounds, that are called song birds.
"The male is the only real singer in Birdland.

Many females have pretty musical notes that they give when about the nest, and some scraps of song; one or two are quite good musicians, but the great chorus comes from the males.
"These have their seasons for singing, and are not in equal voice during the entire year.