Hoo Hoo Hoo-Hooooo

I had two owls in my front pecan tree last night.  I looked them up, and I believe they were Great Horned Owls.  It was about 8 p.m. and I was watching TV when I thought I heard people talking outside.  As in RIGHT outside.  I stuck my head out the front door, but didn't see anyone.  And then I heard the "hoo hoo hoo-hooooo" right over my head.  Surprised, I reached in, turned off my porch light and stepped out.  At the same time, my neighbor across the street stepped out, looking up.  She called, "where is it?"  I said, "You could hear it too??  It's over here, in my tree."  We heard more hooting... and then not one but two large owls flew out of the tree.  VERY cool.  I spent about 30 minutes after that reading about them online.  I did my preliminary identification from my bird book which described the hooting, and the brief flash of pale grey I saw on a very large wingspan.   I'm going to start looking for them at dusk.  I'd heard one before, and talked with a neighbor about it, but never heard it that nearby!