We have lots of upland game birds in Pennsylvania but none of them have head plumes like this.  You have to visit the western U.S. to find birds with topknots.

Gambel’s quail (Callipepla gambelii) live in the southwest, including southern Nevada.  Though they can fly they prefer to walk or run away from danger, their topknots bobbing as they go.  It makes them look kind of festive, almost silly.

What are the head plumes for?

I read that during courtship the male stands high on his legs, puffs himself out and bows to the ground bobbing his head.  This makes his head plumes quiver and shows the rusty top of his head to his potential mate.  You’d think this would impress his lady but studies have shown the plumes themselves make no difference in mate selection.

So the question is still open:  Why do they wear deely boppers?

Maybe they just like to have fun. 😉

(photo from Wikimedia Commons.  Click on the photo to see the original)