American robins are permanent residents across most of the U.S. Nevertheless, many non-birders claim to see their first robin of the year in March, when the soil thaws and they reappear on suburban lawns in pursuit of earthworms.
In fact, robins are present throughout the year and often form massive flocks during the colder months; during that time, they tend to remain in woodlands and wetlands, feasting primarily on berries. Come early spring, they fan out and large flocks may be seen on farm fields; indeed, I encountered about 1200 robins on fields east of Columbia, Missouri, this morning.
Most American robins that summer in Canada do migrate south into the U.S. for the winter and the southernmost regions of the U.S. may only host robins during that season. Wherever they might be, robins consume a mix of berries, insects, earthworms and other invertebrates. When they do pair off and nest, many select sites near the neatly-trimmed lawns of human society and are thus among our best known bird species.
