Bird feathers aren't blue. Hey, don't shoot the messenger.
Bird feathers aren't really blue. Blue is a rare color in birds. Their feathers are a structural color (as opposed to a pigmented color) because it's generated by light interacting with a feather's 3-D arrangement. Different shapes & sizes of these air pockets & keratin make different shades of blue. Photos by Stacy Holcomb and Tyson Vodochodsky