A pair calling to eachother in pine tree. I only got a good look at one but I was able to hear both of their calls. One was a shorter, lower hoot and the other was a longer higher pitched hoot. I think the male has the lower call. I think this behavior is called a 'duet'. They would call and wait for the other to respond and repeat.
Honeymoon Island SP
@ Honeymoon Island - In a large pine tree by a nest. It looked like an older fledgling, still having some fluffy feathers. Looked paler than most.