Comparative Nest Site Habitats in Sharp-Shinned and Cooper's Hawks in Wisconsin

From an analysis of nest site habitat data at 24 Sharp-shinned Hawk (Accipiter striatus) and 52 Cooper's Hawk (A. cooperii) nests in Wisconsin, we conclude that Cooper's Hawks tend to nest in stands with lower densities of taller and larger trees than do Sharp-shinned Hawks, and that Cooper's Hawks also tend to nest in sites with a greater proportion of hardwood cover than Sharp-shinned Hawks. Significant interspecific differences were found in combined habitat types (hardwoods, mixed conifer-hardwoods, and conifer plantations) for nest tree height and nest tree DBH (diameter at breast height); nest height; nest height relative to tree height; canopy height; canopy cover; tall shrub density; tree density; and mean DBH. Nest sites of the two species were similar in terms of understory canopy cover, ground cover, low shrub index, understory tree density, basal area, distance to nearest forest opening, and distance to water. We detected few significant intraspecific differences in nest site habitat, and these only in the Cooper's Hawk.