As its scientific name (Mimus polyglottos) suggests, the Northern Mockingbird is one of nature’s true polyglots (polyglottos means “many-tongued”). It imitates not only birds but, it can also imitate dog barks, frog calls, sounds of machinery, whistles, and bells. It is capable of learning sounds quickly, integrating them onto its own song. So diverse is its repertoire, that no two songs are the same. Mimicry is crucial for sexual selection – the larger the male’s repertoire, the greater is its attractiveness to females.
The Northern Mockingbird has pale grey upperparts, dull whitish grey underparts, and a long tail. Its dark wings have two white wing-bars and large white patches which, together with the white tail sides, are clearly visible in flight. Males and females look alike, though only males sing. The Northern Mockingbird is an omnivore, its diet consists of arthropods, earthworms, fruits, seeds, berries, and seldom, lizards.
The Northern Mockingbird is known for its intelligence, in a paper published in 2009, researchers found that mockingbirds were able to recall an individual human who, earlier in the study, had approached and threatened the mockingbirds' nest. Researchers had one participant stand near a mockingbird nest and touch it, while others avoided the nest. Later, the mockingbirds recognized the intruder and exhibited defensive behavior, while ignoring the other individuals. (wikipedia)
The Northern Mockingbird is the only mockingbird commonly found in North America. This bird is mainly a permanent resident, but northern birds may move south during harsh weather. This species has rarely been observed in Europe.