In the 20 minute gameplay, the part where he frenzies an enemy you can see the shadow of a large bird flying by on the ground.
the fact there is a hawk, doesnt mean they are doing noises
http://www.youtube.com/watch?v=oSL-r9AIEEU&feature=player_detailpage#t=436s
there you see in the left corner above the tower (and compas) a flying creature but
1. you don't know if its a sprite
2. it doesn't do any sound, there some reasons maybe.
If i go out my house, i hear from time to time the birds and raven which would be in a game like skyrim very nice too.
They are clever, for example they break nuts with their beaks or wait if i did (in rare cases) for them ^^
Bats:
http://www.youtube.com/watch?v=oSL-r9AIEEU&feature=player_detailpage#t=904s
do you think it was a trigger or did the bats hanging out there ^^?
p.s. i hope the puzzle with the door and the item is nice, i hope there some more complex one of them.