Kochia (Kochia scoparia): the mention of this weed conjures consternation in the minds of many. But when I think of kochia, I think of sparrows.
October 24, 2022 was a day when it was hard to miss the connection between kochia and sparrows. A snowstorm had pushed through Helena the day before. The glowing golden leaves of the sandbar willows (Salix exigua) were covered with wet snow. It was a reminder that winter was coming. Montana’s six-month season of cold and snow was on its way.
Three other naturalists had joined me on this morning’s survey. Photographer Lea Frye had brought an arsenal of cameras along (check out more of her amazing work here!). Shawn Watts and Scot Bealer were helping to spot birds and track behaviors.
Sparrows in the kochia
And as soon as we got into the kochia, there was a lot to track. Right away I could hear American tree sparrows – recent arrivals from the arctic – making their tip calls from two different directions. Then Lea spotted three more birds as they hopped into the tops of the kochia. These were migrating Lincoln’s sparrows, compact with crisp, dark streaks across their subtle tan breasts. And it was surprising to see them here this late. Lincoln’s sparrows nest in wet, willowy patches in the mountains of Montana and the boreal forest of Canada and Alaska. Here at Sevenmile Creek, they’re a common fall migrant, their numbers typically peaking in late September. By late October, I would generally expect that all of them would have already moved through. But this year, with a mild fall, it was clear that a few Lincoln’s sparrows were lingering longer than expected.
Soon we saw another sparrow perching on top of a kochia plant. Surely this was just one of those that we had already seen? But no – this was a song sparrow, streaky like the Lincoln’s sparrows but larger, its breast white rather than tan. Its streaks were thicker, too, as if they had been painted with a crayon instead of with a fine-tipped pen.
Song sparrows and migration
The song sparrow is the more-adaptable cousin of the Lincoln’s sparrow. It nests across much of Canada, migrating south as winter approaches. But it’s also a common nester in Montana, not just in wet willow thickets in the mountains but also nearly anywhere, high or low, that there is water and good cover. Seeing a song sparrow here, it’s hard to tell what its story might be. Is it one of the song sparrows that nests here, sticking around through the fall to feed on kochia seeds? Or is this bird a migrant, moving south from Canada?
But today, the song sparrows kept popping up in the kochia. By the end of the day, we had counted at least eleven of them here – way more than the handful we find during the breeding season. With so many song sparrows present, it seemed likely that we were seeing some Canadian migrants, moving south in preparation for winter.
White-crowned sparrows from Canada
The American tree sparrows I had heard at first remained secretive. It was only later, in the chokecherries, that we got a good look at them. But soon we saw a fourth species of sparrow perching in the kochia tops. This one, the white-crowned sparrow, was the largest yet. Unstreaked on the breast like the American tree sparrow, we could see its pale-orange beak from a distance. Soon several more of them appeared, a small flock. All of these white-crowned sparrows were this summer’s hatchlings, their striped heads brown, not the striking black-and-white of the adults.
Eventually we counted at least eight of them. They looked at us quizzically as they fed on kochia seeds. Like the Lincoln’s sparrows, these white-crowns were unusually late migrants. En route from their birthplaces in the boreal forest of Canada or Alaska, they were stopping here to stock up on seeds as they fled the approaching winter. Soon, like the Lincoln’s sparrows, they would be gone, not to be seen again in Montana until the spring. (Note: like Lincoln’s sparrows, there are also white-crowned sparrows that nest in the mountains of Montana. But those birds have a dark stripe not only behind the eye, but also in front of it. Based on this distinction, we could tell that these migrants were from the more northerly, boreal forest population.)
Whew! So many sparrows! No wonder some people dismiss them all as “little brown birds.” But like the weedy kochia that feeds them, I believe sparrows are far more interesting than people often assume. And with a bit of practice, they aren’t all that hard to tell apart. Let’s review these four:
Lincoln’s sparrow: Small, with a very pointy bill. Breast with fine, dark streaks on an orange-tan background.
Song sparrow: A bit larger, with a broader, more triangular bill. Breast with wider streaks on a white background.
White-crowned sparrow: One of our largest sparrows, with a yellow or orange bill. Breast solid gray, without streaks or spots. Adults have black-and-white stripes on their heads. Immatures have chestnut-brown stripes instead.
American tree sparrow: Breast grayish like a white-crowned sparrow, but with a dark central spot. Upper part of the bill gray, lower part yellow. Chestnut-striped head.
The sparrows kept appearing. There seemed to be dozens, maybe more. After all, we only had four sets of eyes, and there were thousands of kochia plants where sparrows could hide. Maybe there were 50 sparrows in here today, maybe more.
At one point, we saw five song sparrows perching together. Others made unidentifiable lispy calls nearby. And each time a bird popped into view, we had to check to see if it was something new.
“There’s so many species in these little groups that, positionally, you can’t say what’s what,” Scot remarked.
Watching for rarities and other surprises
Earlier, Shawn had posed the important question of what other species we might hope to see here. And so it was that we kept our eyes open for the rarer possibilities, as well. We watched for Harris’s sparrows, with their massive pink bills. White-throated sparrows, with a prominent yellow spot in front of their eye. Swamp sparrows, like a rarer version of a Lincoln’s sparrow and without strong breast streaks. Fox sparrows, resembling the song sparrow but with their breast streaks made up of reddish rows of vees.
We kept our eyes peeled, but none of these rarities materialized. Suddenly, Scot noticed something unusual. It fell out of the sky in the gray blink of an eye, disappearing among the kochia. Or had Scot only imagined it? We waited. Nothing seemed to have changed. The sparrows kept perching and calling. Snow dripped slowly from the kochia.
And then, minutes later, we saw it well. A sharp-shinned hawk, petite and ferocious. It leapt up from the kochia, disturbed from its attempt at ambushing the sparrows. There it perched in the chokecherries, a tiny predator, intent on a sparrow lunch.
Here was the food web, right in front of our eyes. From kochia seed to sparrow crop to a sharp-shinned hawk’s lunch. The last link in this chain was delayed, for a time. But here or in the next kochia stand along the route of its migration, the sharp-shinned hawk would surely try again.
Kochia, the hated weed
To most people, kochia is a weed. Native to Asia and eastern Europe, it’s an annual that has an amazing propensity to thrive along roadsides and in the disturbed soil of crop fields. People spray herbicides so often to control it that kochia has become resistant to several of them. As an annual, kochia’s strategy is to grow fast, produce a cornucopia of seeds, and then get out. Here at Sevenmile Creek, kochia has benefited from soil disturbance by excavators during stream restoration work. This patch of weeds is a short-lived phenomenon. In a few years, perennials like smooth brome (Bromus inermis) will outcompete it.
Kochia, the sparrows’ food
But to sparrows, the very traits that make kochia the bane of farmers make it a popular fall food source. It’s common and it thrives where few other plants manage to grow. It’s loaded with seeds. Its dense stands provide shelter from the weather and from predators.
So what does all of this mean? Is kochia good, or is it bad? As with all plants, it’s difficult to make such a simplistic value judgment. If you’re trying to grow wheat, kochia probably isn’t your favorite plant. But if you’re a sparrow looking for seeds at the tail end of fall migration, it might be just the ticket.
I probably wouldn’t recommend planting kochia in your yard for wildlife habitat. If you’re looking for seed-rich annuals that like disturbed soil, I’d recommend some of our native plants instead. Think of pit-seed goosefoot (Chenopodium berlandieri), giant-seed goosefoot (Chenopodium simplex), common sunflower (Helianthus annuus), and perhaps marsh elder (Iva xanthifolia).
But if you find a thick patch of kochia in the fall, don’t just call it rude names. Grab your binoculars and take a slow walk through it. And let me know which sparrows you find.
Friesen, L.F., Beckie, H.J., Warwick, S.I., & Acker, R.C.V. (2009). The biology of Canadian weeds. 138. Kochia scoparia (L.) Schrad. Canadian Journal of Plant Science 89:141-167. Retrieved from https://cdnsciencepub.com/doi/pdf/10.4141/CJPS08057