It is indeed a Western Screech Owl. Tiny compared to the big old GH Owls.You know, I would love to know.
From hearing them, we know we have screech, pygmy, great horned and saw-whet at various times in the year. It's easy (and fun!) to tell their calls as they're so unique. For the last couple years the great horned calls have been very distant. But we hear screech nearby pretty regularly. So I wouldn't have thought it's a great horned. But you bring up a good point. His ears are pretty tall.
My wife is the birder in the family, I'll let her know your thoughts and I'm sure it'll get some good conversation going .