They can be quite loud. I’ve done a lot of backpacking/camping, so I’ve heard them often. Regardless if I’m with someone or alone, I can’t help myself from replying, ‘Me, that’s who.’
And no staci, we will not be shooting owls.
A few years ago at my gun club’s winter party a stripper with an owl tattoo on her back was bouncing in my lap, and I yelled out ‘Ooouuww’ (as in ouch). She stopped bouncing and looked back at me, ‘Huh?’ Whereupon I said, ‘There’s an owl on your back.’