We had a Barred Owl hooting outside out house for the last several nights. Not only did it hoot the usual, "Who-cooks-for-you", but it also let out another, less commonly heard, Barred Owl sound, a loud scream "Aahhoooo". Makes the hair on the back of your neck stand up when you hear it.
One time we were in MA at our old home doing a midnight owl census. We got out of the car, paused to listen and right over our heads a Barred Owl flew silently in and gave this loud scream. Our hearts just about stopped, we forgot to breathe and our brains scrambled though our mental file cabinets of loud scary sounds one hears in the Northeastern woods at night. Finally, exhaling, we realized it was a Barred Owl, whew!