As I make my way around the frozen Kettle Pond at Faville Grove Sanctuary, flocks of American Tree Sparrows flutter from weed patch to weed patch, foraging along the snow-dusted ground and knocking seeds loose from the tops of dried plants. It’s no coincidence that I find myself amongst the tree sparrows—I’m spreading wetland seed in areas where invasive reed canary grass has been eliminated, to try to establish native plant communities. The tree sparrows, however, are making use of the flush of annual, high seed yielding plants that colonize areas where reed canary grass has been removed. As I sow a diverse mix of native plants, the tree sparrows communicate with one another in soft, pleasant twitters, unconcerned with my trampling presence. If anything, they may appreciate my rustling through the dried stalks of ragweed, grasses, goldenrods and other delights, shedding their seeds as I go. Effective foraging is of utmost importance to the tree sparrow, who must eat around thirty percent of their weight in food each day to make it through the winter.
American Tree Sparrow feeding on seeds in the winter (photo by Andy Reago & Chrissy McClarren).
Breeding far north at the tundra line in Canada, tree sparrows make their way south in fall, becoming frequent visitors at feeders, field edges, hedgerows, open forests and pastures in Wisconsin throughout winter. During their summer around the northern treeline, their diet is largely insectivorous—consuming moths, caterpillars, wasps, flies, beetles, leafhoppers and more. This protein-rich diet aids in raising their young, who are reared in nests made of moss, grass, bark and twigs, often lined with feathers. These nests are typically built at the base of a shrub, nestled in a tussock of grass.
I admire the hardiness of these flocks of tree sparrows, undaunted by the whipping wisps of snow that I try to shrug off as I continue around the Kettle Pond. It’s satisfying to think that the seeds I spread will become a future food source for these industrious birds, as the wetland communities around the Kettle Pond continue to establish.
Written by Tucker Sanborn, Faville Grove Sanctuary land steward
Cover photo by Kelly Colgan Azar. An American Tree Sparrow perched in the snow holding a twig.
