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)
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)
American robins occur mainly in woodlands, gardens, orchards, lawns, and fields. They search for food (forage) in areas of open ground or short grass. They nest and roost in the edges of woodland or scattered trees and shrubs. 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. Suburban and agricultural areas often provide these kinds of habitats so American robins are common near humans.
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 from their winter range. The breeding season extends from April through July. American robins are one of the first birds to begin laying eggs each spring. They normally have two or three sets of young (broods) in each breeding season. 3 to 5 eggs are laid in each clutch. ("Clutch" means the group of eggs laid in one nest attempt. "Brood" means the number of baby birds that hatch out of the eggs, so the brood may be smaller than the clutch.)
A new nest is built for each clutch of eggs. The female robin builds the cup-shaped nest. The outer foundation is made from long coarse grass, twigs, paper, and feathers woven together. She smears mud onto the inner bowl with her breast. She later lines the inner bowl with fine grass or other soft material. This lining helps cushion the eggs.
The nest can be located on the ground or high up in trees. They are most commonly found 5 to 15 feet above ground. Robin's nests might be in a dense bush, in the crotch of trees, or on window ledges or other human structures. All of these provide a firm support and protection from rain. In northern areas the first clutch is generally placed in an evergreen tree or shrub. The later clutches are laid in a deciduous tree.
Eggs are incubated by the female, which means that she sits on the nest to keep the eggs warm until they hatch. After about 14 days of incubation the eggs hatch. She continues to feed and brood (keep them warm by sitting on them) 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. Fledging is when baby birds leave the nest. About two weeks after fledging, young American robins become capable of sustained flight.
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)
American robins are active during the day. Almost all populations are migratory.
American robins are social birds, but they are more social in winter than in summer. During the winter, they gather 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 large flocks break up into smaller flocks during the day, to feed on fruits and berries.
During the summer, American robins are less social because they are defending breeding territories. 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.
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)
American robins feed on a mixture of fruits, berries, earthworms, and insects such as beetle grubs, caterpillars, and grasshoppers. Their diet usually consists of about 40% insects and 60% fruits and berries. However, American robins are flexible and will eat whichever food is most available. American robins get a lot of moisture from the foods they eat, especially juicy berries and insects, but they also may need to drink free standing water from pools.
American robins may mob, or attack, 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, which means that they spend a lot of time watching for predators. They may feed in loose flocks, so that they can also watch other robins for reactions to predators.
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)
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.
American robins are effective in controlling insects that may damage crops and gardens, such as beetles.
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.
Tanya Dewey (author, editor), Animal Diversity Web.
Candice Middlebrook (author), University of Michigan-Ann Arbor.
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.