KILLER COLD: And what's with all these robins?
Concerned posts about song birds and loads of robins populate up social media
American robins, you seen one, you’ve seen a hundred—especially in recent days as an extended period of cold envelopes this part of the country.
Many songbird species are having a hard time as sub-freezing temperatures persist and snow threatens to cover food sources ground feeders rely upon. Robins, especially, are a visible harbinger of these hard times.
It’s all over social media. “I don’t think I’ve ever seen this many robins in one place!”
“Me too!”
Me three.
Large flocks of robins reported by residents across Oklahoma and Texas recently seem unusual but what people are witnessing is only as unusual as this long-running cold spell. It raises a chance for us all to learn a little more about the incredible social and digestive adaptations of Turdus migratorius and how that might reflect on other species that are gutting it out these days.
FAMILY: Turdidae / GENUS: Turdus / SPECIES: T. migratorius
Be honest, when you saw that I wrote “digestive adaptations of Turdus migratorius” you expected jokes about something like repetitive explosive sounds emitted from the south side of northbound grandpa.
We are above such giggles here.
Turdidae is a family name of North American thrushes, which includes eastern bluebirds and the hermit thrushes many Oklahomans recognize. The robin actually gets its common name from a European flycatcher of that name that also has a red breast. It is a tiny flycatcher, but there are similarities.
The American Robin arguably this country’s most widely recognized songbird. It bears the same color chest as its European namesake but little else genetically.
It is that European songster that appears commonly in Old World myths, literature and poetry as “robin redbreast,” not the robin most Americans picture when they see that word.
But the common little red-breasted bird of Europe also adapted well to living around humans, makes use of their homes and barns for nesting, and also lays eggs sky blue in color. It was celebrated in literature for brightening the gray winter landscape in Great Britain as some, but not all, would stay through the season. And it was also widely celebrated in literature as a harbinger of spring, as is the case in North America.
Our winter (springtime) birds
Think of a robin and a vision comes to mind of a bird playing tug-o-war with an earthworm on the lawn after a spring rain. While some do migrate south to Southwest Texas, Mexico the Louisiana Coast and Florida in winter, they nest as far north as Alaska and are documented year-round residents of every state south of Canada, according to field guides.
Numbers from the Tulsa Audubon Society’s Christmas Bird Count show the mid-December effort tallied 1,343 robins in December 2020 and 5,023 the year prior.
“They are gregarious birds and you’ll often see them in flocks of 100 or more,” said Dan Reinking, a senior biologist at the Sutton Avian Research Center and author of the Oklahoma Breeding Bird Atlas.
The extended cold might be bringing flocks we don’t often notice into greater view because they are feeding more actively and because they are targeting fruit trees and berry bushes that are common in suburban backyards, he said.
Flocking together is a common survival strategy during migration, finding food sources and confusing predators for any number of bird species.
Reinking knew of no strategy that has robins flocking or roosting together to find warmth, although the flock of several dozen I spied on the frost-free roof of a local office building that was obviously shedding some heat was no accident. They will indeed crowd into a sheltered or warm spot.
“They aren’t stupid,” Reinking said.
Of Turdus and Frugivores
Reinking said American Robins are known for their ability to switch from a chiefly fruit-based diet in fall and winter to one that relies on insects and invertebrates in the spring and summer.
A quick reference search on the birds does not turn up articles about the robins as insectivores but as frugivores (fruit eaters) with a digestive system that adjusts to a slower digestive process in the spring and summer to pull needed nutrients from a protein-heavy diet. They digest crickets more than one and a half times slower than berries, according to a May 1992 research paper printed in the American Journal of Physiology.
A lot of people who enjoy feeding birds have figured out they can scatter dried blueberries or cranberries, soaked raisins or cut grapes, bits of apple or other fruits and suet balls on the ground to feed robins in the winter.
During this unusually long cold and snowy spell expect to see unusual concentrations of songbirds in survival mode. They will find shelter and warmth where they can. Many likely will perish. They can use all the help they can get.
Fruits apparently are what the robins are after. That is their natural winter food.
A robin in my backyard seemed to be making due with bits of sunflower chips scattered below a finch feeder but it disappeared after a few days—perhaps to join one of the huge flocks I’ve seen pulling berries off all manner of trees and bushes all across town.
