Nest Site Selection and Productivity of Great Horned Owls in Central Minnesota
Abstract
Thirty-three active nests (16 artificial, 17 natural) of the Great Horned Owl (Bubo virginianus) were found in central Minnesota in 1977. Sixteen of the 17 natural nests were originally built by the Red-tailed Hawk (Buteo jamaicensis). Average nest height was 14 m; 42% of the nests were in northern pin oak (Quercus ellipsoidalis); 79 percent in edge areas, 21 percent in woodlot interiors. Nests averaged 0.59 km from the closest human dwelling and 0.58 km from the closest graded road. Nest density in a thoroughly searched area was 0.21 per km2. Utilization of artificial nest platforms was 52 percent. The first incubating owl was seen on 20 February; the latest clutch was laid during the first week in April. Five of 7 clutches contained two eggs; 10 of 19 successful nests contained two nestlings. Forty-two percent of initial nesting attempts failed. Successful nests produced 1.8 young per nest. Artificial nests were less successful than natural nests, probably because of more human activity at artificial nest sites. An unusual distraction display involving an adult owl is described.
