Add some watered down white glue to felt and it will get stiff and hold it shape when dry. The glue dries clear.  It seems like a shot of steam might make it shrink up too.

Yep steam works on felt. It is how you can re-block a felt hat. You place it over a wooden shape of the hat then hit it with steam.   As Snail mentioned white glue (PVA) or even starch in water can be used to stiffen felt.

So..this project was put on hold.  However, with another con around the corner, I am reviving it to a degree.  Gonna start off a bit smaller, and attempt more of a 1 1/2-2 year old version of Big Bird.  A bit of baby Big Bird's roundness but with more height.  Going to stay under 6 feet, and wear the head on my head.  Might still only use one arm so I can attempt a movable mouth, still debating on that one.  This character will be dressed as Robin from DC Comics, so that will limit the feathers needed.  Wont be perfect, but should be recognizable.  Still intend on doing the full version one day, but "baby steps" :D 

Sound interesting, keep us updated.

Sad thing is my paint skills are much better than my drawing ability.  Anyway, this is the general idea.  Beak may only be about 2 feet long, shirt will be a 2x or 3x store bought Robin shirt with cape.  Left arm will be on chest, carrying Radar dressed as Batman.  Mask will hopefully be at eye level. 



Regarding the mouthplate, any recommendations on controller tutorials? 

Ok now I get it now, Radar is Big Bird's teddy bear, had to look that one up. I love your idea.

Since the mouth is going to be right at your own mouth level you may want to try and "attach" it to your lower jaw. Strap around the back of the head then you need one that runs up and over the head to help keep the snug against your jaw. When you open your mouth the lower beak moves. Unlike with a mouth puppet the lower jaw of the puppet is not simply tilting down it is actually fully dropping down. More like how a vent doll or marionettes mouth may work. Don't know that there are really any tutorials out there for this so your first step would be to simply make the lower beak and figure out how to best secure it to your lower jaw. Then build the upper part of the head and the upper beak so it fits almost like a hat down over that. Now the fabric covering over that needs to allow space so the lower jaw can drop so yes when you close the jaw you have some extra fabric at the back of the beak but you should be able to camouflage this with feathers some. 

I don't think you are going to be able to really get your hand up into the head operate the mouth which is why I suggested the above. The other route would be to construct the beak the same way your would a mouth puppet mouth plate and then use bike cables that run down the sleeve to one of your hands so you can operate the mouth.  Don't forget though you need to be able to see out easily if you are going to con and be able to breath. Don't want you fainting. Philip had a video on how to use pvc pipe to create a spring clip of sorts that would work for operation of the mouth opening and closing.  I'll have to see if I can find it.

Found the video!

This may be helpful also.

Thanks for the video Shawn!  Do you think foam core would hold up to the bike cable method in that video?