This mod adds flying bird, bat and gryphon races to Skyrim for PCs and NPCs. Birds have all-new avian heads and head parts (crests, ears, horns because why not) with complete chargen and expression morphs. Crests and ears show expressions. Birds have claw hands and feet. They have wings courtesy of "Animated Wings Ultimate" by Anton over on Nexus.

There's enough variety in the parts to create a wide range of birds: ravens, eagles, songbirds, parrots, Skeksis. Bats come in leaf-nose and flying fox varieties. 
 
Clawfeet use my adaptation of the high heels mechanism to give digitigrade feet, if you choose that option. Don't try to put boots on them--the birds will just take them off again. 
 
Details
 
In this version
 

• Ulri (raven), Eagle, Griffon, Songbird, and Talis/vulture races. I haven't done anything fancy with the races, just gave them each a different set of perks and abilities so you have something to play with.
  • Use the racemenu setup to get your PC looking as you like. There are a few sliders that don't do anything, but most of them are useful and some of them are intuitive. The races have presets showing some of what you can do. Check the dirt slider--sometimes it has overall face patterns.
    
• Bats!
  • Various face shading. There's a dirt texture that gives you dark ears.
  • Ear shape is on the mouth morph. Sorry about that. Maybe I'll be arsed to make a separate racemenu slider one day.
  • The eye depth slider changes the size of the eyes from tiny to large. Only choose bat eyes if you use this. (I can't keep Racemenu from showing you Khajiit eyes as well.)
  • There are a few different complexions, for leaf noses and fox noses, and for furry ears or the big bat ears. You want to select a complexion that works with your nose.
  • Muzzle/nose tints are in three places; "laugh lines" for the muzzle, "eyeliner" for the part around the nose, and "nose" for the nose itself. The leaf nose uses eyeliner + nose; the fox nose uses nose only, and you'll want the muzzle and "eyeliner" to match to cover the whole muzzle.
    
• There's a separate digitigrade feet patch. Base mod is plantigrade bird feet, so you can wear boots. I think if you wear open-toed boots it looks weird. So don't. With the digitigrade patch, NPCs will take boots off.
• NPC file. Load it up to have bird or bat followers. Adds a flock of birds of each race in a different place in Skyrim. Bird followers fly when you do and will fight from the air. Find their campsite or wait for them at an inn to recruit them. Most are friendly so you can just ask one to join you. As with the races I haven't tried to be really creative but they should be adequate followers with a range of abilities. There's a book in each camp that gives you some details on the races and adds markers for the camps to your map. A few birds with wings take up a lot of room, so if you're running a mod that adds a bunch of NPCs to inns you may find them awfully crowded in the evening.
• • Ulri - Camp in the saddle between the exit from the Helgen cave and the south gate to Falkreath. They go to the Sleeping Giant Inn in the evening.
  • Eagle - Camp just southwest of the Thalmor Embassy. Relax at the Winking Skeever in the evening.
  • Griffon - Camp on a rocky outcrop on the plains between Whiterun and Rorikstead. At the Rorikstead inn in the evening.
  • Songbirds - Camp southwest of Falkreath, right up against the mountain range. At Dead Man's Drink in the evening.
  • Talis - Camp in the badlands of Eastmarch south of Kynesgrove. At Braidwood Inn in the evening. 
  • Bats - Cave southeast of Markarth. They bum around Markarth in the afternoons and congregate in the Sliver-Blood Inn in the evening.
    
  
  

 
Wings and Flying
 
lDelta6l has updated the flying mods and it's pretty much fabulous. Wings are much easier for me to handle, so each race gets their own wings on startup, no need for potions. Flying is pretty intuitive and the animations are really nice. There are no collisions while flying and you really zoom along, but that's tolerable.
 
Wings and flying are optional if you don't want to hassle with all that.
 
Problems and Issues
 

• There are some glitches with the flying. Generally just fiddling--pausing in the air, going into and out of sneak on the ground--fixes them.
• No collisions while flying. Don't fly into things, it's bad.
• Don't expect kissing animations--or blow job animations--or drinking from a cup animations--to work at all reasonably with a beak. Sucks to be a bird.
  

 
Installation
 
Install in this order:

• RaceCompatibility
• Animated Wings Ultimate depends on the following. Install according to AWU's instructions:
  • Flying Mod
  • Flying Mod Overhaul
  • Flying Mod Rework
    
• Animated Wings Ultimate
  

 
Wait, you're NOT DONE! Before you can fly, you have to do the following:
 

• Start the game, get out of character edit, let MCM do its thing
• Go to the AWU mod page and set the control keys. I use "G" held for 1.5 seconds as the wing toggle button and "G" tapped twice as the flight button.
• Then from the Powers menu, use the "Wings" power. Your wings will disappear.
• From the Powers menu, use the "Endow <something> Wings" power. (The name is different depending on your race.) Your wings will come back. Now you can fly.
  

 
You just have to do that once at the beginning of the game. From then on, you can just fly. 
 
Credits

• Ulri and Talis races are the invention of @GDelscribe - appearance and lore follow their design. 
• Erect schlong by @MadMansGun
  

Good with this mod

• Open Cities of Skyrim -- you should be able to fly over the walls when you're a bird.
• DynDOLOD -- Up in the air, your eyes are on the horizon. You should be able to see what's out there. Look in the DynDOLOD manual about how to handle Shrine of Azura replacers and do what it says. Also there are special instructions for handling Open Cities.
  

 
For Modders
 
The birds (not the bats) have tintmasks in 256 and 2048 sizes. By default, the size is 2048 so you can set up your characters in RaceMenu. If you're creating NPCs you need the smaller files--navigate to the tintmask folder and copy the contents of the subfolder Size256 up to the parent folder. That way CK won't freak.
 
Getting the NPCs to have colored wings was a trick, because the skin color isn't reliably applied to the wings, so wing color has to be baked in. There are a set of keywords "BDB_Keyword_<some color>". If you give your NPC one of those keywords, the  wings script will apply wings of the right color.