Long-tailed gray-and-white songbird of the southern United States able to mimic songs of other birds; SYN. mocker, Mimus polyglotktos. /> North American songbird Mimus polyglottos of the mimic thrush family Mimidae, found in the US and Mexico. About 25 cm/10 in long, it is brownish gray, with white markings on the black wings and tail. It is remarkable for its ability to mimic the songs of other species.