I was standing out in a 400-acre wet prairie just north of our Kankakee Sand office, placidly harvesting seeds when I hear the crackling, sizzling Zzzzap! like the sound of an electrical circuit shorting out. With exactly zero electric lines running through that particular prairie, what could have made that sound?
Then I noticed a large willow patch… and where there is a willow patch at Kankakee Sands, there may be a sedge wren (Cistothorus platensis) singing its electrical sounding song.
Sedge wrens are a rare treat to see and hear, because they are a shy and skittish bird. Unlike the chatty, boisterous, easily-viewed house wren, the sedge wren avoids being seen. Even when frightened, the sedge wren will rarely take flight. Instead, it will run on the ground beneath vegetation. It may take flight, but only briefly, before fluttering to the ground to escape notice.
The sedge wren is an even more exciting find because it is state endangered in Indiana. Habitat loss and conversion are the main causes of its decline. However, at Kankakee Sands we have many acres of suitable, wet habitat with plenty of willows. And where there are willows, there is a way for the sedge wren to feed, mate, nest and raise young. Thanks to the restored habitat at Kankakee Sands, we get to enjoy its song during the months of April through October each year.
While doing a birding survey last May at Kankakee Sands, I had the good fortune of glimpsing a sedge wren. Like all male and female sedge wrens, he was a small, four-inch, round-bellied bird with fine streaks of white and brown on the top of its head and back, and white horizontal bands on its wings. His beak was narrow, and sharp!
Given its aversion to being seen, listening for the song of a male sedge wren may be the best way to locate it in nature. Find a wet meadow, or shallow marsh, devoid of cattails, but with many grasses, sedges and willows, and listen for a series of three or four accelerating sharp chirps that are followed by an electric trill. Chap-chap-chap chaprrrrrrr. Also keep an ear out for the sound of two marbles tapping, chadt-chadt-chadt, which is the call that both males and females make to indicate a threat to signal location.
During mating season, males will make nearly a dozen nests in their territory, allowing the female to select the one that will be used. The nests are woven into living shrubs, grasses or sedges, no higher than three feet above ground, and well hidden from view. The dome-shaped nests are constructed out of grasses and sedges and have a small entry hole in the side.
Females line their nest of choice with feathers and fine grasses. They then lay two to eight unmarked, moderately glossy, white eggs. To reduce nearby competition during nesting season, adult sedge wrens may use their sharp-pointed beaks to puncture the eggs of sedge wrens and other small birds who nest nearby.
Sedge wrens forage on the ground, eating such six-legged insects as beetles, moths, grasshoppers, flies, and ants. Their diet also includes creatures with more legs, such as caterpillars and spiders.
As the earth begins to warm, and the insects begin to inhabit the prairies, the sedge wrens will be returning from the warmer climates of southeastern United States and northern Mexico to breed in the Great Lakes region and southcentral Canada. Along with many species of the migratory song birds, sedge wrens will soon be at our Kankakee Sands doorstep.
Come out to Kankakee Sands this spring and summer for a listen for a wren in the willows. The electric song of the sedge wren is worth the trip!
The Nature Conservancy’s Kankakee Sands is an 8,300-acre prairie and savanna habitat in Northwest Indiana, open every day of the year for public enjoyment. For more information about Kankakee Sands, visit www.nature.org/KankakeeSands or call the office at 219-285-2184.