NOTES: NESTING PATTERNS OF RED-TAILED HAWKS AND GREAT-HORNED OWLS IN SOUTH-CEN- TRAL KANSAS

Red-tailed hawks (Buteo jamaicensis) and great-horned owls (Bubo virginianus) can influence the nesting behavior of each other through direct competition for nesting sites. For instance, owls begin nesting before hawks and, thus, can use nests from the previous year and prevent hawks from occupying those sites (Orians and Kuhl- man 1956, Gilmer et al. 1983, Minor et al. 1993). However, both species sometimes kill the nestlings of the other (Craig- head and Craighead 1956, Bosakowski et al. 1989). The objective of my study was to investigate nesting patterns of these two raptors at the edge of the tallgrass prairie over a 22 yr-period and compare these findings with those from previous studies (Alberta; McInvaille and Keith 1974, Ohio; Kirkley and Springer 1980, North Dakota; Gilmer et al. 1983, Utah; Bosakowski et al. 1989, New York; Minor et al. 1993, New Jersey and New York; Smith et al. 1999). Specifically, I examined the influence of annual population sizes, nest density, distance to the nearest neighboring nest, dispersion of nests and overall pattern of usage on nesting ecology of red-tailed hawks and great-horned owls. My study occurred across a 104 km2 area in south-central Kansas. The shape of the study area was rectangular and bisected west to east by highway K-254 from Kechi, Kansas, to the intersection with K-196. Along the highway, there was one range-township section to the north and one to the south, hence the rectangular shape. The land itself consisted of a patchwork of farms, pastures, and houses including three small towns (Kechi, Benton and Towanda). The area represented the western edge of tallgrass prairie of the Flint Hills region