Update: This article was originally written in 2020, but this year is wonderfully another year of abundant Henslow’s Sparrows at Faville Grove Sanctuary!
The Henslow’s sparrow is a small songbird with a dull brown body and a streaked breast. This bird is restricted to open habitats, typically grasslands, of the midwest and northeast. Over winter, they spend their time in longleaf pine and bog habitats of the southern U.S. The pairing of globally rare breeding and wintering habitat makes the bird rare across its range. Endangered in seven states and threatened in Wisconsin, the Henslow’s Sparrow would seem a banner bird for grassland conservation.
Singing Henslow’s Sparrow (photo by Arlene Koziol).
Yet, the Henslow’s Sparrow lacks the iconic status of the Dickcissel or meadowlark. Their understated plumage and faint call—a simple tsillik—undercut zealous heaves. David Sibley describes the call as a “feeble hiccup.” I’ve heard it described as a dripping sink or an old television turning on.
Additionally, the bird is notoriously difficult to spot. Hiding in a dense accumulation of litter a Henslow’s Sparrow will whistle a call, unseen. If approached, the bird often flees on foot, their brown feathers matching the dullness of a few years’ foliage. The nest resides on or near the ground, where the female incubates eggs for approximately 11 days. Chicks will occupy the nest for about nine days, being fed a diet of grasshoppers and caterpillars.
As far as managing for Henslow’s habitat, the birds present an interesting dilemma. On one hand, they need two to three years of litter accumulation in order to breed in an area. Conversely, the birds tolerate a low amount of brush and need dense stands of grass for suitable habitat.
Faville Grove prairie (photo by Madison Audubon).
Burning will maintain the open habitat and stimulate grasses, but the sparrows dislike nesting in recently burned areas. A patchwork of burning, like we have here at Faville Grove, can encourage Henslow’s Sparrows to nest in an area. Areas with multiple years of standing dead vegetation provide cover and nesting areas for these discrete birds. Recently burned prairie provides good foraging habitat, and the dense cover of new growth can hide fledgling chicks.
Over the past few weeks, the interns and I have stumbled on Henslow’s Sparrows throughout the sanctuary. It’s easy to get distracted by the calls of dozens of other birds, but we eventually hone in on the Henslow’s repetitive calls. Standing in a field of smooth brome, the calls seemed bromidic, or trite. While perhaps not the most charismatic bird, the Henslow’s Sparrow represents functioning prairie ecosystems, a patchwork of grassland habitat, and one of the most understated calls of any bird. You can easily miss the birds, but once you find themyou know you’re on a special piece of land.
Written by Drew Harry, Faville Grove Sanctuary land steward
Cover image: The inconspicuous Henslow’s Sparrow perched on a twig in a prairie (photo by Arlene Koziol).
