Wild Things: Robins go south in winter, or don’t they?

An American robin in winter about to grab another mouthful of winterberry holly fruits.

By ED KANZE

While I was growing up, my parents taught me the truism that robins fly south for the winter. It seemed logical. We never saw the birds in winter at our house.

But as I grew up and began wandering further afield, and as I began to take an earnest interest in wildlife, I began seeing robins in winter, not rarely, but often.

Digging into the conundrum of robins flying south versus robins not flying south, one has to embrace contradictory truths. A great many robins do fly South for the winter. It’s possible that every robin you shared your yard, your bugs, and your earthworms with in summer crosses the state line every fall and heads for Georgia, or somewhere warmer where the ground doesn’t entirely freeze. But it’s also possible that you see robins in winter. These may well be different robins. If the winter robins look larger than summer robins, that may be because they in fact are larger. Robins range pretty far up in Canada, and up there, the average size is bigger than your breeding robins of summertime.

Given that robins, like most birds, pack thick insulation under their contour feathers, the problem winter poses in your neighborhood likely has more to do with food scarcity than cold. What to eat when the ground’s frozen? A winter robin can’t yank earthworms out of soil as hard as concrete. Feeding options are limited.

Some robins, however, don’t seem to mind switching over to a diet of fruit in winter. They eat fruit in summer, too, but with fatty, protein-rich insects on easy offer, their diet tends to be diversified. In winter, a northern robin turns mainly to fruit.

Most fruits don’t hang around through winter, so if you want to entertain robins in, say, February, you’re going to need the right plants to attract them. One that serves the purpose is winterberry holly, which abounds in damp ground. It’s called winterberry because birds tend to ignore the fruits until there’s nothing much else on offer. I bet winterberries don’t taste good but I am not about to find out. To humans, holly fruits are poisonous.

Cranberry viburnums, which are often grown ornamentally, hold fruit through the winter, too, but the blazing red globes, which are tart and astringent to put it mildly, tend to wind up the last of last choices. At our place, wild cranberry viburnum fruits tend to hang on into a second year, although robins eat a few of them.

A great thing about planting shrubs to feed winter robins is you get a big bang for your buck and labor. You get brilliantly colored fruits at a time of year when vibrant hues are in short supply, and as a bonus, nature may give you robins.

If I were going to plant to attract robins, I’d be drawn to the vine known to botanists as Celastrus scandens. The rest of us call it American bittersweet. This is a plant absent or rare in many places, perhaps because its habitat has been invaded by the also beautiful but problematic Oriental bittersweet, Celastrus orbiculatus. The American species, perhaps because it’s native and is affected by more factors that limit its growth, tends not to take over a woods the way the introduced species commonly does. (In cases where the American does get bossy, it can be pruned or cut down.) American bittersweet has somewhat elongated leaves and orange-and-red fruits. The fruits are borne at the end of short side branches. On the non-natives, which have leaves nearly round, the generally yellow-and-red fruits hug the main stems. All bittersweet fruits, like all holly fruits, are poisonous to humans. It’s important when planting them to pick locations where unaccompanied children won’t be active.

If you already have bittersweet vines, and you already have hollies or cranberry viburnums or both, you may already have winter robins. Keep your eyes out.