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Turdus migratoriusAmerican robin

By Tanya Dewey and Candice Middlebrook

Geographic Range

American robins are native to the Nearctic region. They occur year-round in southern Canada from Newfoundland to British Columbia, throughout most of the United States and along the Sierra Madre into southern Mexico. They migrate south for the winter, going as far as southern Mexico and Guatemala. In summer they are found as far north as northernmost Canada and Alaska. American robins are the most abundant and widespread North American thrush. (Sallabanks and James, 1999)

Habitat

American robins occur mainly in woodlands, gardens, orchards, lawns, and fields. They prefer areas of open ground or short grass for foraging, with woodland or a few scattered trees and shrubs nearby for nesting and roosting. Suburban and agricultural areas often provide these kinds of habitats so American robins are common near humans. They need dense shrubs and small trees in which to build their nests. They build nests deep in dense foliage to protect their young from predators. (Sallabanks and James, 1999)

Physical Description

American robins are birds that measure 25 cm in length and average 77 g in weight. Males are only slightly larger than females. They are brown on their backs, reddish on the breast, and white on their lower belly and under their tail feathers. Their throats are white, streaked with black. They have white crescents above and below their eyes. Females are slightly paler in color than males. Young American robins have dark spots on their breasts and are also paler in color than adult males. (Sallabanks and James, 1999)

  • Sexual Dimorphism
  • male more colorful
  • Average mass
    77 g
    2.71 oz
  • Average mass
    75.5 g
    2.66 oz
    AnAge
  • Range length
    23 to 28 cm
    9.06 to 11.02 in
  • Average length
    25 cm
    9.84 in
  • Range wingspan
    119 to 137 mm
    4.69 to 5.39 in

Reproduction

Males and females form a pair bond during breeding season and while raising their young. (Sallabanks and James, 1999)

American robins breed in the spring shortly after returning to their summer range (north) from their winter range (south). The breeding season extends from April through July. American robins are one of the first birds to begin laying eggs and normally have two or three sets of young, or broods, in each breeding season. The cup-shaped nest is built by the female, who builds the outer foundation with long coarse grass, twigs, paper, and feathers woven together. She lines the inner bowl with mud, smearing it with her breast and later adding fine grass or other soft material to cushion the eggs. The nest can be located on the ground or high up in trees, but most commonly 5 to 15 feet above ground in a dense bush, in the crotch of trees, or on window ledges or other human structures. All that is needed for the nest is a firm support and protection from rain. A new nest is built to raise each brood. In northern areas the first clutch is generally placed in an evergreen tree or shrub, and the later clutches are laid in a deciduous tree. From 3 to 5 eggs are laid in each clutch. (Sallabanks and James, 1999)

  • Breeding interval
    American robins breed once or twice yearly.
  • Breeding season
    American robins breed from April to July.
  • Range eggs per season
    3 to 5
  • Average eggs per season
    4
    AnAge
  • Average time to hatching
    14 days
  • Average time to hatching
    13 days
    AnAge
  • Average fledging age
    13 days
  • Average age at sexual or reproductive maturity (female)
    1 years
  • Average age at sexual or reproductive maturity (male)
    1 years

Eggs are incubated by the female. After about 14 days of incubation the eggs hatch. She continues to feed and brood the chicks while they are very young. When the nestlings become older the female broods them only at night or during bad weather. Baby birds leave the nest about 2 weeks after they have hatched. All babies from a clutch leave the nest within 1 day of each other. Even after leaving the nest, the young birds follow their parents and beg food from them. They remain under cover on the ground during this time. About two weeks after fledging, young American robins become capable of sustained flight. (Sallabanks and James, 1999)

  • Parental Investment
  • altricial
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • male
      • female
    • protecting
      • male
      • female
  • pre-independence
    • provisioning
      • male
      • female
    • protecting
      • male
      • female

Lifespan/Longevity

One wild bird lived to be almost 14 years old, though most American robins in the wild will live about 2 years. Only about one quarter of all young American robins will survive the summer in which they were born. (Sallabanks and James, 1999)

  • Range lifespan
    Status: wild
    14 (high) years
  • Average lifespan
    Status: wild
    2 years
  • Average lifespan
    Status: wild
    167 months
    Bird Banding Laboratory

Behavior

American robins are active mostly during the day. They are social birds, especially during the winter when they are gathered in large numbers on their winter grounds. They assemble in large flocks at night, often in a secluded swamp or area of dense vegetation, where they roost in the trees. These winter aggregations break up during the day to feed in smaller flocks on fruits and berries. American robins defend breeding territories during the summer and are less social during that time. Young American robins remain in the area of their nest for their first 4 months of life. They gather in mixed-age flocks when it becomes time to depart for their winter grounds. Almost all populations of American robins are migratory. (Sallabanks and James, 1999)

Communication and Perception

Soon after hatching nestlings begin to beg for food by chirping. Adult American robins use chirping or chucking to warn of the presence of a predator. Males begin to sing in the late winter and early spring. This song is a familiar sound in the springtime and sounds something like 'cheerily, cheer up, cheer up, cheerily, cheer up.' American robins sing frequently throughout the day, but particularly early in the morning. They most often sing from a perching spot high in a tree. (Sallabanks and James, 1999)

Food Habits

American Robins feed on a mixture of both wild and cultivated fruits, berries, earthworms, and insects such as beetle grubs, caterpillars, and grasshoppers. Robins are flexible and will turn to whichever food is most readily accessible, although the diet generally consists of approximately 40% invertebrates, 60% fruits and berries. (Sallabanks and James, 1999)

  • Animal Foods
  • eggs
  • insects
  • terrestrial non-insect arthropods
  • terrestrial worms
  • Plant Foods
  • fruit

Predation

American robins may mob small predators, such as blue jays and snakes. They also produce chirping and chucking sounds as warning calls.

Predators on young and adults differ somewhat. Eggs and young are often eaten by different types of squirrels, snakes, and birds such as blue jays, common grackles, American crows, and common ravens. Adult American robins are preyed upon by hawks, cats, and larger snakes.

American robins are vigilant when feeding, they may feed in loose flocks, so that they can also watch other robins for reactions to predators. (Sallabanks and James, 1999)

Ecosystem Roles

American robins are important as prey items to their predators because there are so many of them. They also act to control some insect populations and to disperse the seeds of the fruits they eat. (Sallabanks and James, 1999)

  • Ecosystem Impact
  • disperses seeds

Economic Importance for Humans: Positive

American robins are effective in controlling insects that may damage crops and gardens, such as beetles.

  • Positive Impacts
  • controls pest population

Economic Importance for Humans: Negative

Part of the American robin's diet may include berries, which can reduce the number of berries harvested every year by cultivators. It has also been reported that male American robins have pecked at and damaged windowpanes, windshields, hubcaps, and other polished surfaces, apparently reacting to their own reflections.

  • Negative Impacts
  • crop pest

Conservation Status

American robins are successful birds, having been able to adapt to human alteration of the landscape. At one time, they were killed for meat in some southern States, and the meat was considered a delicacy. They are now protected throughout their range by the U.S. Migratory Bird Protection Act.

Contributors

Tanya Dewey (author, editor), Animal Diversity Web.

Candice Middlebrook (author), 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.

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

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.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

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

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.

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.

riparian

Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).

scrub forest

scrub forests develop in areas that experience dry seasons.

seasonal breeding

breeding is confined to a particular season

sexual

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

social

associates with others of its species; forms social groups.

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.

urban

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

visual

uses sight to communicate

References

Pough, Richard H. 1946. Audubon Land Bird Guide. Doubleday and Company, New York.

Burton M. and Bruton R. 1980. The New Funk and Wagnalls Illustrated wildlife Encyclopedia, BPC Publishing Limited, 1:91-92.

Burke, Ken. 1983. How to Attract Birds. Orhtho Books, San Francisco.

Sallabanks, R., R. James. 1999. American Robin (Turdus migratorius). Birds of North America, 462: 1-20.

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