A Barred Owl has been hooting away all summer north of our house, near the southern end of the Shelton Lakes Greenway, around Buddington Road and Great Oak Circle. Instead of the steady "hoo, hoo" of the Great Horned Owl, which I used to hear on occasion, I now hear a hooting that has a weird trailing off on the last note. It's commonly described as "Who cooks for you? Who cooks for you ALL?" The "All" note sounds oddly like an elephant.
Here's a sound file. Barred Owls and Great Horned Owls apparently don't mix very well, so their territories tend not to overlap much. That would explain why I don't hear the Great Horned Owls this summer now that I'm hearing the Barred Owl.