to the spring dawn chorus of birds—to us, the intense, wonderful sound of winter going away; to birds, a competitive madhouse of males trying to outdo each other, attract a mate and pass on genetic material to future generations.
In suburban and urban areas, the sweet racket is coming mostly from robins, cardinals, titmice, chickadees, house finches and wrens. In many rural areas, the dawn chorus may be laced with the more complicated calls of numerous warbler species, but often with the upbeat song of robins included in the mix.
We don’t think twice about robins being a part of Missouri’s bird life, but in fact they were not always so common here as they are today. In spring and summer, robins eat lots of earthworms. Earthworms live in moist, soft soil they can move around in. Around the time of Missouri statehood, as settlers moved westward across the United States and established towns and agricultural areas, they converted millions of acres of prairies, forests and other natural communities to cropland and pastures.
Since then, we have continued to convert natural landscapes into lawns, golf courses, parks and cemeteries, often accompanied by irrigation systems. All of these land use changes created millions of acres of short grass, soft soil and easy access to lots of earthworms and other soft invertebrates that robins eat. Thus, robins have come to thrive in Missouri, and they breed and winter in nearly every other state as well.
“Robins are found in a huge variety of habitats,” said Dr. Greg Butcher, director of Bird Conservation for the National Audubon Society, “and one of them happens to be suburbia.” Human development, including suburbia and farms, has not only produced a lot of good earthworm-foraging territory, but also, Dr. Butcher notes, more sources of fruits.
In the colder months, when soil hardens or freezes, robins switch from eating invertebrates to fruits. In fall, huge flocks of robins, some numbering in the thousands, migrate to lower elevations or southward in search of sources of fruit like chokecherries and berries of hawthorn, dogwood and sumac. Many robins live in Missouri year-round; those here in winter will wander from fruit source to fruit source. It seems that every winter I have seen snowy ground mottled with the bright orange remains of bittersweet berries, left in the wake of a hungry sweep of robins.
People have helped increase fruit