Response of Northern Harriers and Short-Eared Owls to Grassland Management in Illinois

Abstract

We studied habitat selection by northern harriers (Circus cyaneus) and short-eared owls (Asio flammeus) on 2 intensively managed grassland sanctuary complexes in southeastern Illinois to determine the influence of grassland management on nest placement. Northern barriers showed a tendency (P < 0.001) to locate their nests in fields not disturbed by recent management activities (within the last 12 months). Overall, northern harrier nest placement was not influenced by whether fields were dominated by native or nonnative grasses (P = 0.307), Short-eared owls were irruptive breeders on these grasslands, and habitat selection could only be assessed in 1 year (1990). In 1990, all short-eared owl nests were located in fields disturbed by grassland management activities within the last 12 months. Although northern harriers are believed to be area-sensitive in the Midwest, grassland area did not influence nest-site selection for northern harriers on our sanctuaries (P = 0.622). Northern harriers and short-eared owls have generally contrasting habitat preferences. To provide appropriate habitats for both species, a mix of both managed and idle grasslands must be provided.