Darleen Flaherty of Taylor, Mich., writes, "Several Michigan friends and I spotted robins in various locations in the lower half of Michigan's lower peninsula in February. We saw them when the temperature was in the 40s, but then our weather turned colder and snow returned.""How do robins survive winter conditions?" I've never seen a robin at any of my hanging feeders, nor eating snacks off the cement that I offer for other critters.""Will the robins we saw in February be doomed to die because there are no worms to be had? We'd love for you to write about robins in your column."Winter must be winding down because I'm getting letters and emails about winter robins. Are they back early? Did they ever leave? What do they eat? That's the gist of most of the queries. Here's what happening.
Unlike warblers, swallows, and other songbirds that migrate to avoid severe Northern winters, robins are hardy and flexible. The extent of their annual migration is influenced by several factors, so seeing robins in winter isn't unusual. But even in years when robins escape detection, some while away the colder months in the deep woods where few of us venture regularly. Talk to anyone who hikes the winter woods, however, and you'll hear tales of flocks of robins every year.Large winter flocks of robins are typical in the Southeastern and Gulf Coast states, though serious birders can usually come up with a few winter robins just about anywhere. But large flocks of winter robins are always a sight to behold.Winter robin abundance is most influenced by two factors: snow cover and food availability. In comparing robin abundance to snow cover, Cornell University's Lab of Ornithology reports that areas with less than 5 inches of snow cover typically have lots of robins, while areas with more than 5 inches of snow cover have fewer robins. Heavier snow cover means lower temperatures and food that's more difficult to find, so robins move south to more favorable conditions.
Furthermore, if food is abundant, robins can thrive in surprisingly cold temperatures if coupled with minimal snowfall. Fruit-bearing trees and shrubs such as cherries and grapes sustain robins during the winter months. Earthworms and other invertebrates are warm weather fare. Being dietary opportunists, robins remain where food is abundant until supplies are exhausted. Then they move on.One reason robins linger farther north today compared to 50 years ago, especially during mild winters, is the popularity of ornamental fruit trees in urban and suburban areas. We may plant crab apples, hollies, and mountain ashes for their visual appeal, but robins value their fruits. Our horticultural habits have helped create a winter haven for robins.Another advantage to less frequent and shorter migrations is that robins have that much less distance to travel again in the spring. Thus they can return to their breeding territories earlier and in better condition.Though people may see flocks of scores or even hundreds of robins during the day while they forage for fruits and berries, the largest and most impressive groups assemble just before dusk. Thousands of robins roost in conifers or other dense cover. And they are sometimes joined by thousands of cowbirds, grackles, and starlings. Such a sight is impressive, unless you happen to park your car under the roost tree.At dawn, these large roosting flocks break up into many smaller feeding flocks that might travel as far as 20 miles to a food source. At day's end, they return to the roost for a safe night's sleep.Readers also often ask if robins can be attracted to feeders. They can, but not with seeds. Try offering diced raisins, grapes or craisins. Or, thinking more long-term, plant a few fruit-bearing trees and shrubs around the house. Robins also love live food. I've watched hungry robins take mouthfuls of mealworms repeatedly, especially when they are feeding nestlings.Robins are a poor sign of spring. If you choose to measure the arrival of warmer weather by the occurrence of migratory birds, let hummingbirds and wood thrushes be your harbingers of spring.Send questions and comments to Dr. Scott Shalaway, 2222 Fish Ridge Road, Cameron, WV 26033 or email firstname.lastname@example.org