Many of us are familiar with the refrain, “When the red, red robin comes bob-bob-bobbing along”. Robins are often the first birds we learn to identify, and are associated with the arrival of spring.
This can vary a bit, since the Robins time their arrival with the 37 isotherm---we weather map showing locations with average temperatures of 37 degrees. This can be a few days different from year to year. A key element is the vertical migration of earthworms, their favorite food. Earthworms generally emerge when the ground temperature is 36 degrees.
In the spring, male Robins travel together, arriving 10 days to 2 weeks ahead of the females. Good nesting sites, near food supplies are at a premium, and the earlier individual birds arrive, the better their chance of claiming a good site.
Females build nests and begin laying eggs shortly after arriving, depending on weather conditions. A nest normally contains 3-5 blue eggs, and a pair will nest at least twice, sometimes 3 times in a summer. When the first group of fledglings leave the nest, the father bird takes over their care while the female lays another hatch. He will feed them and teach them to feed on their own. He will do the same for the next hatch, although the mother may help if she does not nest a third time.
Summer Robins eat mostly earthworms along with a variety of other worms and caterpillars. They will eat an occasional berry, but heavy use of berries and other fruits occurs mostly in the winter months when worms are not available.
In September the Robins become restless, and by the first week of October are mostly gone. In the early fall migration, birds from this area often migrate to a marshy area some 60 miles north of St. Louis. There is a large area of matted reeds which are intertwined and provide good shelter from weather as well as protection from predators. Before dark, robins will arrive by the thousands for overnight roosting. While a few will spend the winter, most migrate further south with many ending up in Florida or Texas.
Robins migrate in flocks, sometimes interspersed with other birds. One large flock was counted at 60,000 birds. They migrate at 30-36 mph and will travel 1-200 miles per day.
In late winter Robins become restless and prepare to return to the same area year after year. They migrate at 30-36 miles per hour, covering 1-200 miles per day. Male Robins can be identified by a darker head and brighter breast plumage. Recently a Robin with a white head was spotted and photographed near St. Joseph. This is rare, but does occur.
To attract Robins, do not remove all leaves from the grounds as these provide good hunting grounds.
Robins are among the first of the migrants to arrive, and quickly become a common sight around town. Spring is almost here when we seem a large number of robins. They know.