A comparison of raptor densities and habitat use in Kansas cropland and rangeland ecosystems

We counted raptors on line transects along roads to assess densities, speci es diversity, and habitat selection of winter raptors between cropland and rangeland habitats in eastern Kansas. We conducted counts every 2 wk betwee n September-March 1994-98. Species diversity indices did not differ between the two habitats (P = 0.15). We calculated density estimates and cover typ e selection for Red-tailed Hawks (Buteo jamaicensis), Northern Harriers (Ci rcus cyaneus), and American Kestrels (Falco sparverius). Red-tailed Hawks a nd Northern Harrier densities were higher in cropland, while kestrel densit ies did not differ between the two habitats. All three species across both habitats had a general preference for idleland habitat. We believe three fa ctors could explain the higher raptor densities in cropland: increased prey abundance, increased visibility of prey associated with harvested agricult ure fields, and/or a higher relative amount of preferred hunting habitat.