Can you help identify this bird in Louisville Kentucky? This bird shows up in my back yard every night. It is calling and sometimes I hear a bird in the distance calling back. I think its an owl but I haven't seen it yet. Any ideas what it is?

To me that sounds like the distinctive "who cooks for you" call of the Barred owl.

Compare with the recordings available from the Audubon Society, Cornell's All About Birds, and many others such as this YouTube video from a Cornell Lab Bird Cam of a Barred owl calling from its nest.