While conducting roadside eagle surveys on 27 November 2012 in west-central Utah, we found two Great Horned Owls (Bubo virginianus) roosting in a group of six deciduous trees along the southern boundary of a 3-ha farm lot. Upon investigating further, we found an additional four owls also roosting in this group of trees. The owls were dispersed at random in the trees, with the average distance between owls being approximately 1 m, and the largest distance between owls approximately 5 m. The number of owls per tree never exceeded two, and two owls perched in trees alone. Our proximity to the owls caused three birds to flush from the trees and retreat to a nearby hayloft 100 m to the west.
The presence of more than two adult Great Horned Owls is counter to the species' typical roosting behavior. The Great Horned Owl is an aggressive and highly...