Aloha, if you haven't downloaded the Merlin bird app yet, we highly recommend it. You can see what birds occur in your region and it is a great tool for ID-ing birds by ear in the field or for leisure in your backyard. The Barn Owl and Pueo make distinctly different sounds. If you go to the Short-eared Owl 'Sounds' section on the app, the second and last call on the list are the most common sounds we hear coming from the Pueo.
Check out: http://merlin.allaboutbirds.org/