American Robin-Nature's Troubadours
If you have ever lived somewhere that American Robins breed, a spring without their bright, lilting “cheerily, cheer up, cheerily, cheer up” song lacks something magical. Yet in 1959, Michigan State University (my alma mater—go Spartans!) faced this catastrophe. In the early 1950s, campus arbor specialists began trying to eradicate Dutch elm disease on campus by spraying the thousands of elm trees with DDT. The insecticide manufacturer had assured them that the spray was not harmful to birds. But the oily residue stayed on the leaves; the leaves fell to the ground; the earthworms ate the leaves; the robins ate the earthworms. Within a week after each new wave of migrant robins arrived, all of them were dead. By 1959, robins had been completely extirpated from the bucolic, 5,200-acre campus. Faculty ornithologists eventually identified the culprit—as few as 11 earthworms delivered a lethal dose of poison to a robin—and stopped the use of DDT locally. This investigation became one of the cornerstones of Rachel Carson’s powerful and ground-breaking Silent Spring, which resulted in the banning of DDT as a pesticide throughout the U.S. And happily, the MSU robin population had returned to its pre-1950s level within two decades.
The American Robin is the largest species in the thrush family, which includes not only all three bluebird species but also some of the most talented songsters in the avian world. Among my favorites are the songs of the Hermit Thrush, Swainson’s Thrush, Veery, and the inimitable Wood Thrush—one of which surprised local birders by visiting Palomar Mountain in November! American Robins inhabit every state in the continental U.S. and much of Canada. Saddled with the easily ridiculed scientific name of Turdus migratorius, the American Robin is known in Latin as the “wandering” (migratorius) “thrush” (turdus). (Since most thrushes wander—migrate—to some degree, it’s not really clear why the robin was singled out for this particular moniker.) Its common name arose from homesick European settlers in the U.S., who thought the birds looked like the English Robin, commonly found in Europe (but to which our robins are not closely related).
Even if you don’t live with robins, they are among the most familiar birds. Slate gray upperparts, white markings around the eyes, rusty-orange breast and flanks, and a dark tail with white corners mark this bird. Stunning, lovely, and pretty much unmistakable. Adult males and females look a lot alike, although you can often differentiate them by the color of their heads: Males’ heads are darker—almost black—than their gray-brown backs while females’ heads are grayer and show less contrast to their backs.
In San Diego County, unlike much of the rest of the U.S., the American Robin is a traditional harbinger of winter rather than spring. A robin’s spring and summer diet is 90% soft-bodied invertebrates, especially earthworms. But in fall and winter, it flips to 90% fruit. At that point, the robin becomes an irregular visitor here, common in some winters, scarce in others, as flocks roam in search of berry-bearing plants such as toyon, wild grape, California coffeeberry, and many ornamentals. In the mountains, the robin is fairly common among conifers. The importance of orchards as American Robin habitat was highlighted during field work for The San Diego County Bird Atlas. The region from Bonsall east to Valley Center, with extensively planted avocado and citrus groves, emerged as one of the robin’s major population centers. And of course, lawns with berry-laden ornamental plants offer the robin traditional suitable habitat as urbanization has expanded.
Robins move nomadically through these habitats. As winter visitors, they are widespread but very irregular—abundant in some years, scarce in others. Even within the county, invasions take place at different times. American Robins don’t follow a rigid schedule of migration, at least in southern California. But in general, if robins don’t breed in your area, these winter visitors begin to arrive in October and leave for their breeding grounds starting in April.
On those breeding grounds, American Robins greet the morning long before most humans and other birds are up—as much as an hour before dawn. This behavior gave rise to the adage “The early bird catches the worm.” During breeding season, robins are also the last to sing in the long summer twilight after sunset.
In my Oceanside neighborhood, I generally hear the “chup-chup-chup” call of our first winter robins in our fruit-laden toyon bushes in mid- to late October. I’m immediately transported to my earlier life in the Midwest, surrounded by robins. The one whose lovely, lilting song woke me up at 5 a.m. and that same one that sang me to bed at night. The one I can still hear as that eight-year-old version of myself in April, sitting cross-legged under the giant maple tree in my backyard in southwestern Michigan, knowing that good things beckoned with the ending of a long, snowy winter and the emergence of spring as announced by the robins. Harbingers, they may be. Lyrical troubadours, they are. Welcome, always.
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Photo credit: Steve Brad, www.seatosierrabirds.org