Flying low over the floodplain prairies, marshes, and bog relicts at Faville Grove Sanctuary, the Northern Harrier silently scans and listens for prey. With famed eyesight and a rounded, owl-like face designed to channel the faintest noises, the harrier adeptly haunts grasslands and marshes.
A Northern Harrier hunts over a grassland (photo by Phil Brown).
Preferring mostly open areas of 250 acres or more, the Northern Harrier can be relatively uncommon in southern Wisconsin. The sanctuary’s expansive lowland prairies adjoining the Crawfish River, as well the Kettle Pond and Faville Grove Bog, provide quality habitat for harriers, which make their nests amongst spanning stands of bluejoint, prairie cordgrass, and cattails. Also plentiful are meadow voles, which comprise much of the harrier’s diet. So dependent are they on this particular prey that the number of nests and fledglings corresponds directly to the vole population cycle, which crashes and rebounds roughly every four years.
A male harrier delivers a meal to a female, who catches it in midair (photo by Tom Koerner/USFWS).
Beyond this, harriers have versatile diets, hunting anything from small mammals and birds to amphibians and reptiles. Anyone would be impressed with the harrier’s ability to spy and seize prey through the verdant tangles that shoot up from the rich soil. Further demonstrating their agility and skill, the male will often bring a meal back to the nest and drop it while flying over—the female will catch the meal in midair and return to the nest.
Northern Harriers are relatively easy to spot in flight, holding their wings high in a V-shape. Their white rump patches stand out against the landscapes they glide across. Driving or walking down Prairie Lane or walking the trails that straddle Faville Grove Bog and the Kettle Pond Bog allows one to easily survey the various ecosystems that harriers inhabit.
In much of the midwest, their populations have suffered significantly from the pressures of land conversion and degradation, the agricultural intensification of hayfields and pastures, and the consequences of historic DDT usage. In Wisconsin, there is ample opportunity (and necessity) for grassland restoration. The extensive work done at Faville Grove and other nature preserves have allowed for the return of harriers, but keeping them is the important part. Southern Wisconsin Bird Alliance will remain committed to restoring and maintaining these important habitats for the benefit of all species, including the Northern Harrier and the vole.
Written by Tucker Sanborn, Faville Grove Sanctuary land steward
Cover photo by Grayson Smith/USFWS. A Northern Harrier soars over a prairie with tall grasses.
