American robin

## Cool facts

* + An American Robin can produce three successful broods in one year. On average, though, only 40 percent of nests successfully produce young. Only 25 percent of those fledged young survive to November. From that point on, about half of the robins alive in any year will make it to the next. Despite the fact that a lucky robin can live to be 14 years old, the entire population turns over on average every six years.
	+ Although robins are considered harbingers of spring, many American Robins spend the whole winter in their breeding range. But because they spend more time roosting in trees and less time in your yard, you're much less likely to see them. The number of robins present in the northern parts of the range varies each year with the local conditions.
	+ Robins eat a lot of fruit in fall and winter. When they eat honeysuckle berries exclusively, they sometimes become intoxicated.
	+ Robin roosts can be huge, sometimes including a quarter-million birds during winter. In summer, females sleep at their nests and males gather at roosts. As young robins become independent, they join the males. Female adults go to the roosts only after they have finished nesting.
	+ Robins eat different types of food depending on the time of day: more earthworms in the morning and more fruit later in the day. Because the robin forages largely on lawns, it is vulnerable to pesticide poisoning and can be an important indicator of chemical pollution.
	+ The oldest recorded American Robin was 13 years and 11 months old.

## Facts

The **American robin** (***Turdus migratorius***) is a migratory bird of the true thrush genus and Turdidae, the wider thrush family. It is named after the European robin because of its reddish-orange breast, though the two species are not closely related, with the European robin belonging to the Old World flycatcher family. The American robin is widely distributed throughout North America, wintering from southern Canada to central Mexico and along the Pacific Coast. It is the state bird of Connecticut, Michigan, and Wisconsin.

According to the Partners in Flight database (2019), the American robin is the most abundant landbird in North America (with 370,000,000 individuals), ahead of red-winged blackbirds, introduced European starlings, mourning doves and house finches. It has seven subspecies, but only one of them, the San Lucas robin (*T. m. confinis*) of Baja California Sur, is particularly distinctive, with pale gray-brown underparts.

The American robin is active mostly during the day and assembles in large flocks at night. Its diet consists of invertebrates (such as beetle grubs, earthworms, and caterpillars), fruits, and berries. It is one of the earliest bird species to lay its eggs, beginning to breed shortly after returning to its summer range from its winter range. The robin's nest consists of long coarse grass, twigs, paper, and feathers, and is smeared with mud and often cushioned with grass or other soft materials. It is among the earliest birds to sing at dawn, and its song consists of several discrete units that are repeated.

The adult robin's main predator is the domestic cat; other predators include hawks and snakes. When feeding in flocks, it can be vigilant, watching other birds for reactions to predators. Brown-headed cowbirds (*Molothrus ater*) lay their eggs in robin nests (see brood parasite), but the robins usually reject the egg.

## Distribution and habitat

This bird breeds throughout most of North America, from Alaska and Canada southward to northern Florida and Mexico. While robins occasionally overwinter in the northern part of the United States and southern Canada, most migrate to winter south of Canada from Florida and the Gulf Coast to central Mexico, as well as along the Pacific Coast. Most depart south by the end of August and begin to return north in February and March (exact dates vary with latitude and climate). The distance by which robins migrate varies significantly depending on their initial habitat; a study found that individual robins tagged in Alaska are known to travel as much as 3.5x further across seasons than robins tagged in Massachusetts.

This species is actually a rare vagrant to western Europe, where the majority of records, more than 20, have been in Great Britain. In the autumn of 2003, migration was displaced eastwards leading to massive movements through the eastern U.S., and presumably this is what led to no fewer than three American robins being found in Great Britain, with two attempting to overwinter in 2003–2004, although one was taken by a Eurasian sparrowhawk. A sighting occurred in Great Britain in January 2007. This species has also occurred as a vagrant to Greenland, Jamaica, Hispaniola, Puerto Rico and Belize. Vagrants to Europe, where identified to subspecies, are the eastern subspecies (*T. m. migratorius*), but the Greenland birds also included the Newfoundland subspecies (*T. m. nigrideus*), and some of the southern overshots may have been the southern subspecies (*T. m. achrusterus*).

The American robin's breeding habitat is woodland and more open farmland and urban areas. It becomes less common as a breeder in the southernmost part of the Deep South of the United States, and there prefers large shade trees on lawns. Its winter habitat is similar, but includes more open areas.

## Behavior[edit]

The American robin is active mostly during the day, and on its winter grounds it assembles in large flocks at night to roost in trees in secluded swamps or dense vegetation. The flocks break up during the day when the birds feed on fruits and berries in smaller groups. During the summer, the American robin defends a breeding territory and is less social.

### Diet[edit]

Male American robin with an earthworm
Perching in a tree

The American robin's diet generally consists of around 40 percent small invertebrates (mainly insects), such as earthworms, beetle grubs, caterpillars and grasshoppers, and 60 percent wild and cultivated fruits and berries. Their ability to switch to berries allows them to winter much farther north than most other North American thrushes. They will flock to fermented *Pyracantha* berries, and after eating sufficient quantities will exhibit intoxicated behavior, such as falling over while walking. Robins forage primarily on the ground for soft-bodied invertebrates, and find worms by sight (and sometimes by hearing), pouncing on them and then pulling them up. Nestlings are fed mainly on earthworms and other soft-bodied animal prey. In some areas, robins, particularly of the northwestern subspecies (*T. m. caurinus*), will feed on beaches, taking insects and small mollusks. American robins are common pests of fruit orchards in North America. Due to their insectivorous and frugivorous diet they have evolved to lose sucrase. Brugger & Nelms 1991 find sucrose is unpalatable to them and can be used by humans as a deterrent.

The American robin uses auditory, visual, olfactory and possibly vibrotactile cues to find prey, but vision is the predominant mode of prey detection. It is frequently seen running across lawns picking up earthworms, and its *running and stopping* behavior is a distinguishing characteristic. In addition to hunting visually, it also has the ability to hunt by hearing. Experiments have discovered that it can find earthworms underground by simply using its listening skills. It typically will take several short hops and then cock its head left, right or forward to detect movement of its prey. In urban areas, robins will gather in numbers soon after lawns are mowed or where sprinklers are in use.

### Threats[edit]

Juvenile robins and eggs are preyed upon by squirrels, snakes, and some birds, such as blue jays, California scrub jays, Steller's jays, common grackles, American crows, and common ravens. Adults are primarily taken by *Accipiter* hawks, cats, and larger snakes (especially rat snakes and gopher snakes). Mammals, such as foxes and dogs, are mainly likely to grab fledgling young robins from the ground, while raccoons often prey upon nests and small carnivores such as American martens, ring-tailed cats and long-tailed weasels are agile enough to hunt adults. However, the greatest predatory impact (perhaps alongside domestic cats) is probably from raptorial birds. They may be taken by nearly every variety of North American accipitrid, from the smallest, the sharp-shinned hawk, to one of the two largest, the golden eagle, most every North American falcon from the smallest, the American kestrel, to the largest, the gyrfalcon, and almost all owl species from the northern pygmy owl to the snowy owl. Overall, 28 raptorial bird species are known to hunt American robins. Adult robins are most vulnerable when distracted by breeding activities, though they may also be attacked on the ground or even in flight. However, when feeding in flocks, the American robin is able to remain vigilant and watch other flock members for reactions to predators.

The American robin is known to be a rejecter of cowbird eggs, so brood parasitism by the brown-headed cowbird is rare. Even when it occurs, the parasite's chick does not normally survive to fledging. In a study of 105 juvenile robins, 77.1% were infected with one or more species of endoparasite, with *Syngamus* species the most commonly encountered, found in 57.1% of the birds.

### Breeding[edit]

American robin with nest-making materials
The American robin begins to breed shortly after returning to its summer range. It is one of the first North American bird species to lay eggs, and normally has two to three broods per breeding season, which lasts from April to July.

The nest is most commonly located 1.5–4.5 m (4.9–14.8 ft) above the ground in a dense bush or in a fork between two tree branches, and is built by the female alone. The outer foundation consists of long coarse grass, twigs, paper, and feathers. This is lined with smeared mud and cushioned with fine grass or other soft materials. A new nest is built for each brood, and in northern areas the first clutch is usually placed in an evergreen tree or shrub, while later broods are placed in deciduous trees. The American robin does not shy away from nesting close to human habitations.

A clutch consists of three to five cyan eggs, and is incubated by the female alone. The eggs hatch after 14 days, and the chicks leave the nest a further two weeks later. The altricial chicks are naked and have their eyes closed for the first few days after hatching.

The chicks are fed earthworms, insects, and berries. Waste accumulation does not occur in the nest because the adults collect and take it away. Chicks are fed, and then raise tails for elimination of waste, a solid white clump that is collected by a parent prior to flying off. All chicks in the brood leave the nest within two days of each other. Juveniles become capable of sustained flight two weeks after fledging. Bird banders have found that only 25% of young robins survive their first year. The longest known lifespan of an American robin in the wild is 14 years; the average lifespan is about 2 years.

### Vocalization[edit]

0:47
American robin song
An adult while making an alarm call

The male American robin, as with many thrushes, has a complex and almost continuous song. It is commonly described as a *cheery* carol, made up of discrete units, often repeated, and spliced together into a string with brief pauses in between. The song varies regionally, and its style varies by the time of day. The song period is from late February or early March to late July or early August; some birds, particularly in the east, sing occasionally into September or later. They are often among the first songbirds to sing as dawn rises or hours before, and last as evening sets in. It usually sings from a high perch in a tree. The song of the San Lucas subspecies (*T. m. confinis*) is weaker than that of the eastern subspecies (*T. m. migratorius*), and lacks any clear notes.

The American robin also sings when storms approach and again when storms have passed. In addition to its song, the species has a number of calls used for communicating specific information, such as when a ground predator approaches and when a nest or another American robin is being directly threatened. Even during nesting season, when they exhibit mostly competitive and territorial behavior, they may still band together to drive away a predator.

## Conservation status[edit]

The American robin has an extensive range, estimated at 16,000,000 km2 (6,200,000 sq mi), and a large population of about 370 million individuals. The western subspecies (*T. m. propinquus*) in central California are considered to be expanding their range, as is likely the case elsewhere in the United States. It is threatened by climate change and severe weather, but the population trend appears to be stable, and the species does not approach the vulnerable species thresholds under the population trend criterion (>30% decline over ten years or three generations), and therefore International Union for Conservation of Nature evaluated it as least concern.

At one point, the bird was killed for its meat, but it is now protected throughout its range in the United States by the Migratory Bird Treaty Act.