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Mimus polyglottosnorthern mockingbird

By Eve Breitmeyer

Geographic Range

Northern mockingbirds are distributed throughout North America, including Canada and Mexico. In fact, sightings have been reported as far off the coast as Hawaii (where they were introduced). However, northern mockingbirds are most commonly found in the southern regions of the United States and are most often sighted in Texas and Southern Florida. They breed from northern California, eastern Nebraska, southern Ontario and Atlantic Canada southward to southern Mexico. (Rylander, 2002; Texas Parks & Wildlife Department, 2003; Wild Birds Forever, Date Unknown)

Habitat

Northern mockingbirds prefer open areas and forest edges. They are commonly found in residential areas, farmlands, roadsides, city parks, open grassy areas with thickets and brushy deserts. They require a tree or higher perch from which they can defend their territories. Northern mockingbirds occupy similar habitat year-round. (Nature of New England, 2003; Rylander, 2002; Texas Parks & Wildlife Department, 2003)

Physical Description

Northern mockingbirds are medium-sized birds with long legs and tails, and short, rounded wings. Males are larger than females, ranging from about 22 to 25.5 cm in length and averaging 51 g. Females range from 20.8 to 23.5 cm long and weigh an average of 47 g. Northern mockingbirds have gray-brown upperparts, with a large white patch on each wing and white outer retrices that are conspicuous in flight. Their black bills are long and somewhat decurved. Males and females are similar in appearance, with the exception of difference in size and slightly darker tail feathers on females. Juveniles are similar to adults, but have brown spots on their underparts. (Derrickson and Breitwisch, 1992; Rylander, 2002)

  • Sexual Dimorphism
  • male larger
  • sexes colored or patterned differently
  • Range mass
    47 to 51 g
    1.66 to 1.80 oz
  • Range length
    20.8 to 25.5 cm
    8.19 to 10.04 in

Reproduction

Northern mockingbirds are generally monogamous. Polygyny and bigamy seem to occur only rarely in this species. Breeding pairs remain together for the length of a breeding season, occasionally for life.

Males establish a territory and attempt to attract a female using courtship displays. They may chase the female through the territory while calling, or run along shrub and tree branches, showing her potential nest sites. Males also perform a flight display, which shows off their white wing patches. In the flight display, males sing continuously while flying a few meters into the air and then parachuting slowly back down. (Derrickson and Breitwisch, 1992; Holoweb, 2001; Rylander, 2002)

Northern mockingbirds breed in spring and early summer. Their nests are bulky and cup-like and are made of twigs, cotton, dry leaves, stems, paper, grass and other organic material. Nests are built in shrubs and trees anywhere from one to fifty feet off of the ground. After mating, the female lays two to six eggs (average 4 eggs), which are approximately 24 by 18 mm in size. The eggs are usually a blue to greenish color and may have several brown or reddish spots. Female mockingbirds are the sole incubators of the eggs. The eggs hatch after 11 to 14 days. Though the chicks are altricial at hatching, they leave the nest after 10 to 12 days. When the young fledge, the female usually begins to build a new nest, and the male is active in teaching the young to fly as well as continuing to feed them. The fledglings are independent in 10 to 15 days and reach sexual maturity in one year. Northern mockingbirds can raise 2 to 4 broods a year. (Derrickson and Breitwisch, 1992; Holoweb, 2001; Rylander, 2002)

  • Breeding interval
    Northern mockingbirds can have 2 to 4 broods a year.
  • Breeding season
    Breeding occurs in the spring and early summer.
  • Range eggs per season
    2 to 6
  • Average eggs per season
    4
    AnAge
  • Range time to hatching
    11 to 14 days
  • Range fledging age
    10 to 12 days
  • Range time to independence
    10 to 15 days
  • Average age at sexual or reproductive maturity (female)
    1 years
  • Average age at sexual or reproductive maturity (male)
    1 years

Females incubate the eggs, males do not. However, when the eggs hatch, the female and male are both active in feeding and protecting the altricial young. After the chicks fledge, the female begins to build a new nest for a second brood. During this time, the males teach the young to fly and continue to feed them. (Derrickson and Breitwisch, 1992; Gough, et al., 1998; Sprott and Mazzotti, 2001)

  • Parental Investment
  • no parental involvement
  • altricial
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • male
      • female
    • protecting
      • male
      • female
  • pre-independence
    • provisioning
      • male
    • protecting
      • male

Lifespan/Longevity

Northern mockingbirds have been known to live up to 8 years in the wild. Captive northern mockingbirds have lived up to 20 years. (Derrickson and Breitwisch, 1992; Sprott and Mazzotti, 2001)

  • Range lifespan
    Status: wild
    8 (high) years
  • Range lifespan
    Status: captivity
    20 (high) years
  • Average lifespan
    Status: wild
    178 months
    Bird Banding Laboratory

Behavior

Northern mockingbirds are perhaps best known for their remarkable singing abilities. This species can perform at least 39 songs as well as 50 call notes. Northern mockingbirds also have the ability to mimic sounds such as dogs barking or the songs of other birds.

Northern mockingbirds are solitary and territorial. During the nesting season, they are often very aggressive; they often attack other animals in defense of their territory, including animals as large as cats, dogs and humans

Northern mockingbirds are diurnal. They are also partially migratory. Most individuals that breed in the northern part of the range migrate south for the winter. Those that nest in the southern part of the range are typically year-round residents. (Derrickson and Breitwisch, 1992; Texas Parks & Wildlife Department, 2003)

Home Range

We do not have information on home range for this species at this time.

Communication and Perception

Northern mockingbirds communicate primarily using song. They can perform at least 39 different songs as well as 50 other call notes. They also have the ability to mimic certain sounds such as dogs barking, pianos, sirens and squeaky gates. Song is also an essential part in mating. Males use their song to attract mates and to mark their territory. They sing often, both during the night and day.

Northern mockingbirds also use visual cues to communicate. For example, males perform a “flight display” to attract and court a mate (see Reproduction: Mating Systems). This display integrates auditory and visual methods of communication. (Derrickson and Breitwisch, 1992; Rylander, 2002; Sprott and Mazzotti, 2001)

  • Other Communication Modes
  • mimicry

Food Habits

Northern mockingbirds are omnivores. Their primary food sources are insects, berries and seeds. Insects they eat include beetles (order Coleoptera), ants (order Hymenoptera), grasshoppers (order Orthoptera) and spiders (order Araneae). Plants that are included in their diets are: holly, mulberries, raspberries, dogwood, brambles, grapes and figs. They also eat earthworms, and occasionally small crustaceans and small lizards.

Northern mockingbirds usually forage on the ground or while perched in a tree or shrub. They obtain water by drinking from puddles, river and lake edges and dew and rain droplets that collect on vegetation. (Derrickson and Breitwisch, 1992; Gough, et al., 1998; Holoweb, 2001; Rylander, 2002; Wild Birds Forever, Date Unknown)

  • Animal Foods
  • reptiles
  • insects
  • terrestrial worms
  • aquatic crustaceans
  • Plant Foods
  • seeds, grains, and nuts
  • fruit

Predation

Adult northern mockingbirds are vulnerable to predation by sharp-shinned hawks, screech owls, scrub jays and great horned owls. Incubating females are also occasionally killed by snakes.

Northern mockingbird eggs and chicks are vulnerable to predation by blue jays, fish crows, American crows, snakes and squirrels.

When predators approach the nest, adults give alarm calls. Adults often also mob predators that enter a territory, sometimes striking them. (Derrickson and Breitwisch, 1992)

Ecosystem Roles

Northern mockingbirds play an important role as seed dispersers. They also impact populations of the insects they eat. Northern mockingbirds host several ectoparasites, including blowfly larvae (family Calliphoridae), fleas and mites. Finally, three cowbird species (genus Molothrus) brood parasitize northern mockingbirds. This means that these cowbird species lay eggs in the nests of northern mockingbirds that then raise the cowbird chicks. (Derrickson and Breitwisch, 1992; Sprott and Mazzotti, 2001)

  • Ecosystem Impact
  • disperses seeds

Economic Importance for Humans: Positive

Northern mockingbirds eat insects that humans often consider to be pests. These include beetles, ants, wasps and grasshoppers. They also disperse the seeds of many plants. Humans often study their unique behaviors and vast vocal repertoire. (Sprott and Mazzotti, 2001; Texas Parks & Wildlife Department, 2003)

  • Positive Impacts
  • research and education
  • controls pest population

Economic Importance for Humans: Negative

Northern mockingbirds are often thought of as a nuisance because of their nocturnal singing, which may keep people up at night. Gardeners and farmers may also dislike these birds which often feed on fruits and vegetables, potentially damaging their crops. (Texas Parks & Wildlife Department, 2003)

  • Negative Impacts
  • crop pest

Conservation Status

Northern mockingbird populations are extensive and are not currently of conservation concern. There are an estimated 45,000,000 northern mockingbirds worldwide. This species is protected by the US Migratory Bird Treaty Act. (Karl, 2000)

Contributors

Alaine Camfield (editor), Animal Diversity Web.

Kari Kirschbaum (editor), Animal Diversity Web.

Eve Breitmeyer (author), University of Michigan-Ann Arbor, Phil Myers (editor), Museum of Zoology, University of Michigan-Ann Arbor.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

acoustic

uses sound to communicate

agricultural

living in landscapes dominated by human agriculture.

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

arboreal

Referring to an animal that lives in trees; tree-climbing.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

desert or dunes

in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.

diurnal
  1. active during the day, 2. lasting for one day.
endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

fertilization

union of egg and spermatozoan

introduced

referring to animal species that have been transported to and established populations in regions outside of their natural range, usually through human action.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

migratory

makes seasonal movements between breeding and wintering grounds

mimicry

imitates a communication signal or appearance of another kind of organism

monogamous

Having one mate at a time.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

oceanic islands

islands that are not part of continental shelf areas, they are not, and have never been, connected to a continental land mass, most typically these are volcanic islands.

omnivore

an animal that mainly eats all kinds of things, including plants and animals

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

scrub forest

scrub forests develop in areas that experience dry seasons.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

suburban

living in residential areas on the outskirts of large cities or towns.

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

urban

living in cities and large towns, landscapes dominated by human structures and activity.

visual

uses sight to communicate

References

International Birding Information Resource Data. 2000. ""Northern Mockingbird"" (On-line). i-bird.com. Accessed March 20, 2003 at http://www.i-bird.com/.

Derrickson, K., R. Breitwisch. 1992. Northern mockingbird (Mimus polyglottos). Pp. 1-24 in A Poole, P Stettenheim, F Gill, eds. The Birds of North America, Vol. 7. Philadelphia, PA: The Academy of Natural Sciences and Washington DC: The American Ornithologists Union.

Enature.com, 2003. "Birds: Northern Mockingbird" (On-line). Enature.com. Accessed April 15, 2004 at http://www.enature.com/fieldguide/showSpeciesGS.asp?sort=1&curGroupID=99&display=1&area=99&searchText=northern+mockingbird&curPageNum=1&recnum=BD0136.

Gough, G., J. Sauer, M. Iliff. 1998. "Patuxent Bird Identification Infocenter" (On-line). Accessed April 15, 2004 at http://www.mbr-pwrc.usgs.gov/Infocenter/infocenter.html.

Holoweb, 2001. ""Northern Mockingbird: Mimus polyglottos" (On-line). Animals Identified on the Property or Known to Live in South East Minnesota. Accessed April 15, 2004 at http://www.holoweb.com/cannon/northergn.htm.

Karl, J. 2000. "Mimus polyglottos (Northern mockingbird)" (On-line). Accessed April 15, 2004 at http://imnh.isu.edu/digitalatlas/bio/birds/sngbrd/thrashr/nomo/nomo_mai.htm.

Nature of New England, 2003. ""Northern Mockingbird"" (On-line). Nature of New England. Accessed April 15, 2004 at http://www.nenature.com/NorthernMockingbird.htm.

Rylander, K. 2002. ""Northern Mockingbird"" (On-line). The Handbook of Texas Online. Accessed April 15, 2004 at http://www.tsha.utexas.edu/handbook/online/articles/view/NN/tbn1.html.

Sprott, P., F. Mazzotti. 2001. "Mockingbirds (mimus polyglottos)" (On-line). Edis. Accessed April 15, 2004 at http://edis.ifas.ufl.edu/BODY_UW094.

Texas Parks & Wildlife Department, 2003. "“Nature: Northern Mockingbird”" (On-line). Texas Parks and Wildlife. Accessed April 15, 2004 at http://www.tpwd.state.tx.us/factsheets/birds/mockingbird/mockingbird.htm.

Wild Birds Forever, Date Unknown. "Attracting the Northern Mockingbird" (On-line). Wild Birds Forever. Accessed April 15, 2004 at http://www.birdsforever.com/mock.html.

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