About This File
While perusing my papyrus logs I noticed a scandalous number of script errors centered around birds what the engine calls "critterspawn". I have seen these in my Skyrim as well. I have lots of Worldspace changing mods which add meshes and textures to the worldspace. These types of mods can break other stuff that's locked away in compressed files. So I exported the meshes and textures from the birds and voila no more errors. Plus the birds no longer hover in place.
TLDR: Fixes some bird errors in the game world, including stuck animation.