While my husband was a great sport and agreed to dress up as… BIG BIRD! … he really only wore a hat. I made this easy no-sew DIY Big Bird costume hat for him to wear, while he skipped the yellow getup.
You can wear this big bird costume hat together with a yellow tee and orange pants to turn it into a full-body costume. Aim for something you can reuse after Halloween as pajamas or clothing. My husband chose to wear the hat alone.
I chose a baseball cap for this DIY costume, as it doubles as Big Bird’s beak. Starting with the right structure makes this costume so crazy easy. I did go a little overboard with the wired feathers on top (you can really just glue some feathers directly on) but it was totally worth it!
I challenge you to take this a step further and add pink stripes to the pants (fabric paint, ribbons or felt + glue, or pink duct tape should do the trick.) Put orange socks over your shoes and you have yourself a full body costume!
Place the blue so that it overlaps the pupil a bit. 
5. Assemble your eyes and glue them right above the visor of your cap. You can let them overlap slightly. 
My spouse was a terrific sport and consented to dress as BIG BIRD, but all he actually wore was a hat. He declined the yellow outfit, so I made him this simple no-sew DIY Big Bird hat.
2. Use your white circle as a guide to trace an eyelid in pink.
6. To make the feathers: tape them at the base to the wire.
FAQ
How do you make a boater hat out of paper?