Landscape ecology of the red-tailed hawk: With applications for land-use planning and education.

摘要

I used a multi-scale GIS approach to determine that one to three scales (100m-radius circular plot: nest area; 250m-radius: macrohabitat; 1000m-radius: landscape) are most appropriate to describe Red-tailed Hawk habitat composition.; Red-tailed Hawk reproductive success averaged 80.1% nest success and 1.36 young per active nest over a 14-year period. Productivity for 1994 was greater than other years. Red-tailed Hawk productivity, an index of habitat quality, varied with habitat composition. Wetland area was greater for low productivity sites, indicating that wetlands are not beneficial for Red-tailed Hawk productivity. Road area and high-density urban habitat were greater for high productivity sites, indicating that urban/suburban locations provide high-quality habitat. Higher productivity in urban locations suggests that urban Red-tailed Hawk populations may be source, not sink, populations. Increased nesting on human-made structures in urban locations and enhanced reproductive success for these nests reinforce this hypothesis, and suggest that Red-tailed Hawks are adapting to urban environments.; The Red-tailed Hawk population in southeast Wisconsin is increasing in density and expanding its range into developed areas as it adapts to urban environments. While productivity did not vary significantly with density, the predicted trend (reduced productivity at higher densities) exists. Detecting density-dependence may be difficult because of wide annual variations due to density-independent factors such as weather. While space, and nest site and prey availability may ultimately be the major limiting factors for this population, my study suggests that their effects are not yet detectable in this urban environment.; Red-tailed Hawk habitat in urban/suburban Milwaukee includes large areas of grassland and other herbaceous cover types (e.g., freeways, freeway intersections, parks, golf courses, cemeteries). With Red-tailed Hawks nesting on and hunting from human-made structures in urban areas, woodlands may be less important in urban than rural locations. Hunting habitat and wetlands are consistently present in urban, suburban and rural habitat within nest areas, and therefore, may be important habitat components. Important habitat components can be incorporated into comprehensive land-use plans to allow Red-tailed Hawks to coexist with humans in urban environments.