I once had bad problem with red squirrels getting into my buildings. I eliminated all my bird feeders, and put traps into boat.
Saw almost intimidate reduction in the tree rats and felt pretty smart, until I began to notice the great horned owl hanging out around my house.
Was years ago, but I remember being able to walk around and find him in various locations.
It was fun to watch, but I never did get to see him grab one of the squirrels.