This is year two for the Great-Horned Owls as history tries to repeat itself. Parents moved in early, before the nest owners (Red-shoulded Hawks) could reassert their rights. After all, they had been raising chicks successfully year after year--and now they have to keep building temporary nests as the urgent chick-bearing days approach. See the many years of Hawk Chicks here: http://www.joanrobins.com/Birds/Red-shoulder-Hawk-Nest-Parking