mockingbird

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Any of several species of New World birds of the family Mimidae, especially Mimus polyglottos, a gray and white bird of North America and the Caribbean islands, noted for the ability to mimic the sounds of other birds.

from The Century Dictionary.

• noun In Demerara, a name applied to orioles of the genus Cassicus, and especially to C. ieteronotus, which is often kept as a cage-bird on account of its pleasant note.
• noun In Australia, the lyre-bird, Menura superba: so called on account of its remarkable power of song.
• noun An oscine passerine bird of the subfamily Miminæ and restricted genus Mimus; a mock-bird or mocker.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Zoöl.) A long-tailed gray-and-white songbird of North America (Mimus polyglottos), remarkable for its exact imitations of the notes of other birds. Its back is gray; the tail and wings are blackish, with a white patch on each wing; the outer tail feathers are partly white. Originally its range was confined mostly to the southern states, but by late 19th century it had migrated as far north as New York. The name is also applied to other members of thee same and related genera, found in Mexico, Central America, and the West Indies, such as the blue mockingbird of Mexico, Melanotis caerulescens.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A long-tailed American songbird of the Mimidae family, noted for its ability to mimic calls of other birds.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun long-tailed grey-and-white songbird of the southern United States able to mimic songs of other birds