RTP-area local music and culture

[mike AT mysterycircuits.com (Mike Walters)]

Since the weather's warmed up, my wife and I have opened the windows.
It's not quite AC weather yet. During the early sleeping hours, 3-4am
or so, I've noticed a sound coming from the woods that starts off kind
of like an owl "Hoo-Hoo", and then it evolves to a monkey sound
"Aaah-Aaah-Aaah". The total sounds like
"Hoo-Hoo-Hoo-Hoaah-Hwaah-Ahh-Ahh-Ahh". And then other owl-monkeys join
in. I thought maybe it's deer, but people I've asked seem to think
deer just grunt. I'm confused. I noticed it last year, but I wasn't
sure if I was the only one who heard it. Does anyone know what animal
this sound originates?