Great Horned Owl vocalizations--question

["Debbi B" dgbrusco]

I heard some vocalizations while listening for owls, during the
Christmas Bird Count. Both male and female were vocalizing about at the
same time, and then then the male went into something I haven't heard
before--like "hoo--hoo-hoo-hoo-hoo" perhaps with an exclamation mark,
instead of the usual hoo-rhythm. Has anyone heard or recorded copulation
vocalizations for this owl? I suppose you wouldn't necessarily know if
they were doing that unless you were watching them...
--
/Debbi Brusco/