Northern Mockingbird Facts

The northern mockingbird (Mimus polyglottos) is a common sight in the United States, Central America, and the Caribbean. The bird's common and scientific names refer to its mimicking ability. The scientific name means "many-tongued mimic."

Description

Mockingbirds are medium-sized birds with long legs and black bills. They measure between 8.1 and 11.0 inches long, including a tail that is nearly as long as the body, and weigh between 1.4 and 2.0 ounces. Sexes look alike, but males tend to be slightly bigger than females. Northern mockingbirds have gray upper feathers, white or pale gray underparts, and white-patched wings. Adults have golden eyes. Juveniles are gray with streaks on their backs, spots or streaks on their chests, and gray eyes.

Habitat and Distribution

The northern mockingbird's breeding range potentially extends coast to coast at the U.S.-Canadian border. The bird is a year-round resident further south in North America, Central America, and Caribbean. Birds that live in the northern portion of the year-round range often move further south when the weather turns cold. The mockingbird was introduced to Hawaii in the 1920s and has been observed in southeastern Alaska.

Diet

Mockingbirds are omnivores. The birds feed on earthworms, arthropods, seeds, berries, fruit, and occasionally small vertebrates. The northern mockingbird drinks water from river edges, puddles, dew, or freshly pruned trees.

Behavior

Northern mockingbirds display a distinctive behavior when foraging. They walk on the ground or fly to food and then often spread their wings to display the white patches. Proposed reasons for the behavior are to intimidate prey or predators. Mockingbirds aggressively chase pets and human intruders they perceive as threats to their territory, particularly when nesting. Northern mockingbirds sing all day, into the night, and when there is a full moon. Females sing, but more quietly than males. Males imitate other animals and inanimate objects and may learn 200 songs during their lives. Mockingbirds are highly intelligent and can identify individual humans and animals.

Reproduction and Offspring

Mockingbirds may live all year in a single territory or they may establish separate breeding and wintering territories. Usually, the birds mate for life. The breeding season occurs in the spring and early summer. Males attract mates by pursuing females, running around their territories, singing, and flying to display their wings. The female lays between two and four broods a year, each averaging four pale blue or green blotched eggs. The female incubates the eggs until they hatch, which takes about 11 to 14 days. The male defends the nest during incubation. The hatchlings are altricial, meaning they are completely dependent on their parents at birth. Their eyes open within the first six days of life and they start leaving the nest within 11 to 13 days. Both males and females are sexually mature at one year of age. Adults typically live around 8 year, but one bird in Texas was known to live 14 years, 10 months.

Conservation Status

The International Union for Conservation of Nature (IUCN) classifies the northern mockingbird's conservation as "least concern." The species' population has been stable for the last 40 years.

Threats

Expansion of the mockingbird's range is limited by winter storms and dry weather. The birds have many predators. In addition to natural predators, cats often prey upon eggs and nestlings.

Northern Mockingbirds and Humans

The northern mockingbird is the state bird of Arkansas, Florida, Mississippi, Tennessee, and Texas. Mockingbirds readily raid gardens. They will attack humans and pets they perceive as threats.

Sources

• BirdLife International 2017. Mimus polyglottos. The IUCN Red List of Threatened Species 2017: e.T22711026A111233524. doi:10.2305/IUCN.UK.2017-1.RLTS.T22711026A111233524.en
• Levey, D.J.; Londoño, G. A.; et al. "Urban mockingbirds quickly learn to identify individual humans." Proceedings of the National Academy of Sciences. 22. 106 (22): 8959–8962, 2009. doi:10.1073/pnas.0811422106
• Logan, C.A. "Reproductively dependent song cyclicity in mated male mockingbirds (Mimus polyglottos)." Auk. 100: 404–413, 1983. 
• Mobley, Jason A. Birds of the World. Marshall Cavendish. 2009. ISBN 978-0-7614-7775-4.
• Schrand, B.E.; Stobart, C.C.; Engle, D.B.; Desjardins, R.B.; Farnsworth, G.L. "Nestling Sex Ratios in Two Populations of Northern Mockingbirds." Southeastern Naturalist. 2. 10 (2): 365–370, 2011. doi:10.1656/058.010.0215