Not that they all do it--oh, no, many have only their own beautiful natural song; every Mockingbird has not the power of imitation, but certain members of the tribe acquire a knack of mockery of which they seem quite conscious.
"The Sage Thrasher, though gentle and sociable in its wild state, does not thrive in cages as well as the true Mocker.

It seems to miss the broad expanse of plain and mountain to which it has been used, and seldom lives long in confinement.
"Read what you have written about the size and color of this Thrasher," said the Doctor to Rap.
The Sage Thrasher Length eight inches.
Upper parts gray, tinged with brown.
Under parts white shaded to buff, and spotted thickly on the breast with very dark brown, almost black.
Two white bands on each wing, and white spots on the end of the tail.
A Summer Citizen of the western United States.
A Ground Gleaner, Tree Trapper, and Seed Sower.

THE MOCKINGBIRD "Mammy Bun knows about Mockingbirds," said Dodo.

"She says the bushes were full of them down in Louisiana where she was born, and that sometimes they used to sit on the top of the cabins and sing so loud at night, when the moon shone, that the children couldn't go to sleep, and they had to throw sticks and things at them." "Did the children throw sticks at the birds, or the birds pelt the children ?" laughed the Doctor--for poor Dodo was famous for mixing up her sentences.
"No, no, Uncle Roy, neither; the children's _mothers_ threw the sticks at the Mockers." "What else did Mammy Bun tell you ?" "Lots and lots of things, and a song, too, that her people used to sing about the Mockers, only I can't tell it as she does because you know she has a sort of language all her own." "Suppose we ask mammy to come and tell us about the Mockingbirds herself," said Olive, "May we, father ?" "Certainly, if you can coax her." The children followed Olive to the house and soon returned leading mammy, who was chuckling and out of breath, but evidently very much pleased to be asked.

She could not be persuaded to try the apple-tree perch, so they made her a sort of throne at the foot of the tree and sat respectfully in a row in front of her.