It said “Byawwwwwwwl! Byawwwwwwwl! Byawwwwwwwl!” In a really loud, raspy carrying voice about three times as loud as any yowling tomcat I’ve ever heard, so that at first I thought somebody had hit a cat without killing it. And then it kept going and I was like, “WTF, do we have a really angry owl outside or a bobcat or something?”
(Barn owls. Another cute, elegant animal that makes really startlingly ungodly noises.)