Owlet Chittering and Hooting in Its Sleep

I've always known that owls can talk in their sleep since I've seen and heard Alice do it many times.  But I never had a recorder or video camera handy, and it happens way too fast anyway.

Thanks to dedicated cam viewers, we're finding out new things about owl vocalizations.  Jonnetje from The Netherlands was online in the wee hours of our morning (daytime for her) and she noted an odd vocalization.  I went back to the place in the video she indicated and found this clip.

The owlet on the right is sleeping, but with the sound up you'll hear quiet chitters, but they are annoyed.  (Obviously no one is doing anything to annoy the owlet.)  Shortly after is a mumbled, muffled, high-pitched hoot.  A "sleep hoot" is muffled and mumbled anyway since the gular sac can't expand when their head is settled down while sleeping, but this owlet sounds extra odd because it's vocal apparatus is not developed enough to give a low adult-type hoot.

Notice that the owlet woke itself up with its hoot.  Alice does this sometimes too.

Thanks to all of you who are watching and submitting your observations!