During a recent week-long visit to the Washington D.C. area, finding pockets of nature with plenty of birds was a boon to our sanity. Early in the week, my partner and I drove west to the little town of Linden, Virgina, which provided the nearest access to the Appalachian Trail. Even as we crossed the gravel parking lot toward the oak-filled forest and uphill climb, a wistful-sounding white-throated sparrow sang from the brush. We looked at each other and grinned.
The rhythmic whistle of white-throated sparrows is part of the spring and summer soundtrack of the Northwoods. No hike or paddle is complete without their song. Two decades ago, while my parents helped me pack for a May trip to the Boundary Waters, this was the one song they’d insisted I learn to recognize. Luckily, it wasn’t hard. The white-throat’s pattern of two long starter notes followed by three sets of triplets is often described with the mnemonic “Oh, sweet Canada, Canada, Canada” and is quite distinctive.
But it’s been a month or more since we heard the last sparrow sing goodbye to the Northwoods as they headed south. I felt a little sheepish, realizing I’d never paid much attention to where they were going. Virigina, as it turns out, is in the core of their winter range. As we hiked, it seemed like almost every scritching sound in the underbrush turned out to be a foraging sparrow using their two-footed hops to unearth seeds in the duff. Getting a glimpse of snazzy black-and-white head stripes, yellow near the eyes, and the signature white throat patch confirmed their identity.
Higher up in the trees, cardinals whistled, tufted titmice peter-peter-petered, Carolina wrens chattered energetically, and Carolina chickadees scolded each other. These are common winter compatriots of the white-throated sparrows.
A few days later, we crossed over a babbling brook on a wide wooden bridge and into the “R. Randolph Buckley ‘8-Acre’ Park” in Clifton, Virginia. Large beech trees, sycamores, oaks, maples, and pines, plus musclewood and a blooming witch hazel, welcomed us into this little neighborhood woodland. As we followed our ears to a white-breasted nuthatch high in a pine tree, a song burst out of a bush beside us. The white-throated sparrow riffed on the usual song, experimenting with a gravely “sweet can-a-NA-da can-a!” “Jazzy!” We laughed to each other.
I don’t usually expect birds to sing in their winter habitat. Birds’ songs are typically used to attract mates and defend territories, and therefore are most useful in spring and summer. Many birds get by using simple call notes to communicate within a flock over the winter. So, we figured we were hearing young males practicing for the coming year. That would also explain why the amateurs’ “sub-songs” were tending shorter and with more variations in rhythm and tone. As it turns out, that was only part of the story.
Singing on their wintering grounds is more than just training for the youngsters. It’s an important avenue for learning new songs! In 1999, two ornithologists in western Canada heard white-throated sparrows singing a shorter song. Instead of the triplet “can-a-da,” they heard a doublet, “can-a.” Over the next few years, scientists studied older recordings of the white-throat’s songs, and made new observations, too. In ten years, by 2019, the new song had been adopted as far east as Ontario. Currently, you can only hear the original song in the farthest east populations.
How did the new song spread so quickly when these sparrows breed clear across Canada? They learned from each other on their wintering grounds and then took the new “slang” back home in spring. This goes against traditional wisdom, that young birds learn to sing from their fathers before they leave home. Song spread is facilitated because male sparrows from all over are extra concentrated. They tend to stick to the north end of their winter range—poised for a rapid return to claim a breeding territory in spring—while females go farther south to avoid competition with the males.
Just singing a new song isn’t enough to make birds successful, though. If it’s not recognizable to your own species, or sounds weird, a new song might hurt your breeding success. In this case, females prefer the novelty of the males’ new song, and this reinforces the change.
I’d heard about the white-throated sparrow’s changing songs before, but it wasn’t until I investigated the young birds’ jazzy riff that I realized it had taken over so completely. I’ve been trying to shoehorn their summer songs into the familiar “Oh, sweet Canada” mnemonic, and attributing variation to lazy birds. Now I know that something much more interesting is going on. Just like the sparrows, I learned something new in their winter habitat.
Emily’s award-winning second book, Natural Connections: Dreaming of an Elfin Skimmer, is available to purchase at www.cablemuseum.org/books and at your local independent bookstore, too.
For more than 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. The Museum is open with our brand-new exhibit: “Anaamaagon: Under the Snow.” Our Winter Calendar is open for registration! Follow us on Facebook, Instagram, YouTube, and cablemuseum.org to see what we are up to.
Last Update: Dec 04, 2024 9:01 am CST
