The Northern Mockingbird, Mimus polyglottos, is the only mockingbird commonly found in North America.

The Northern Mockingbird breeds in southeastern Canada, the United States, northern Mexico, the Bahamas, Cayman Islands and the Greater Antilles. It is replaced further south by its closest living relative, the Tropical Mockingbird Mimus gilvus. The endangered Socorro Mockingbird is, contrary to previous opinion, also closely related.

This bird is mainly a permanent resident, but northern birds may move south during harsh weather. This species has occurred in Europe as an extreme rarity.

These birds forage on the ground or in vegetation; they also fly down from a perch to capture food. They mainly eat insects, berries and seeds. While foraging they frequently spread their wings in a peculiar two-step motion to display the white patches. There lacks consensus among ornithologists over whether this behavior is purely a territorial display, or whether the flashing white patches startles insects into giving up their cover.

The Northern Mockingbird builds a twig nest in a dense shrub or tree. It aggressively defends this nest and the surrounding area against other birds and animals, including humans. When a predator is persistent, Mockingbirds from neighboring territories, summoned by a distinct call, may join the attack. Other birds may gather to watch as the Mockingbirds harass the intruder.

Mockingbirds' willingness to nest near houses, loud and frequent songs, and territorial defense often annoy people. John van der Linden, author of the Eastern Birding Central FAQ, reports 25 to 50 percent of the e-mail questions he receives are concerned with how to deal with annoying mockingbirds.

Mockingbirds have a strong preference for certain trees such as maple, sweetgum, and sycamore. They generally avoid pine trees after the other trees have grown their leaves. Also, they have a particular preference for high places, such as the topmost branches of trees. Mockingbirds are often found in urban and suburban areas, where they perch on telephone poles, streetlights, or high points on buildings. While singing on a high perch they will often bolt several feet into the air in a looping motion, with wings outstretched to display their white underside, then land back on the perch without breaking a note. This action serves as a territorial display.