Robins are medium-sized birds with large bellies, long legs and medium-length tails. Adults have dark gray or black heads, gray backs and wings, and bright reddish-brown undersides with a white patch under the tail. Males and females have similar coloration, but females tend to have paler coloration on their heads.

There are some differences in color based on where the robins live. Robins in eastern North America tend to have more vivid coloration compared to their western cousins.

Robins live in forest edges, swampy areas, open clearings, pastures and farmland. They are also extremely common in human-dominated areas, like parks, gardens, backyards and urban areas. 

Some populations breed in the northern United States and Canada and fly south for the winter to the southern U.S., Mexico, and Central America. However, many populations live in colder areas year-round, traveling based on wherever they can find food.

Robins pair up during the breeding season, with males and females working together to raise their young. Parents will aggressively defend their nest from perceived threats, emitting a warning call to alert other robins that a potential predator is nearby. 

Depending on where they live, many local populations of American robins will migrate south in the fall, gathering in huge flocks to make the journey to warmer winter climates. However, it is not uncommon for robins to inhabit colder areas year-round, hunkering down in their nests during the winter months and emerging just before springtime.

Robins usually raise two to three broods per season, with each clutch containing three to five eggs, which are a light "robin's egg" blue in color. A new nest is usually built for each brood. Nests are typically cup-shaped and made from dead grasses and twigs, although in human-populated areas they can include bits of trash like string and newspapers.

Females incubate the eggs, which hatch after about 12-14 days. Both parents take turns feeding worms and small insects to the babies. The hatchlings are ready to fledge, or attempt to fly for the first time, after nine to 16 days’ worth of care. They become capable fliers after about two more weeks, at which point they are ready to strike out on their own.