The American Robin (Turdus migratorius) breeds from most of Canada south, in the mountains, to southern Mexico. The winter range is shifted somewhat to the south. American Robins are found in cities and towns, on lawns, on farmland, and in forests. In winter, they are often associated with berry-bearing trees. In the arid southwestern United States, they summer mainly in coniferous forests in the mountains, rarely in the well-watered lowland suburbs. This common and widespread thrush is often seen running and hopping on lawns searching for earthworms, which are an important part of the diet, along with insects and berries (fruit may account for 60% of the diet year-round). Young are fed mainly on insects and earthworms. Contrary to popular belief, earthworms are located by sight, not sound. American Robins may nest in trees and shrubs, on eaves and ledges of barns, and even on window sills.
The American Robin's rich, rollicking song is often heard very early in the day in spring and summer, before first light. Males arrive on the nesting grounds before females and defend territories by singing (and sometimes fighting). In early courtship, females may be actively pursued by one or several males. The nest is built mainly by the female., usually1 to 8 m above the ground (up to around 20 m). The nest is a cup of grasses, twigs, and debris, worked into a solid foundation of mud and lined with fine grasses and plant fibers. The 3 to 7 pale blue eggs (usually 4) are incubated by the female for 12 to 14 days. Both parents feed the young, but the female more than the male. Parents are very aggressive in defending the nest. Young leave the nest around 14 to 16 days after hatching. Males may continue to care for the fledged young while the female initiates a second brood.
In fall and winter, foraging American Robins may gather in large flocks. Migrating flocks often travel by day. Wintering range and migration habitats may vary a great deal from year to year and location to location, depending on weather and local food supplies.
(Kaufman 1996; AOU 1998; Dunn and Alderfer 2011)