Why are bluebirds blue?

Mountain Bluebird by Myrna Pearman


Unlike other plumage colours, the blue colour of bluebird feathers is not due to a pigment. Rather, it is produced by the unique structure of the feathers themselves and the way they refract the light spectrum. If you take a bluebird feather and crush it, it turns dull gray. Adult bluebirds look different to each other than they do to us because birds’ eyes can detect colour in the ultraviolet (UV) light spectrum. UV waves are invisible to the human eye. This UV coloration may play an important role when it comes to how the birds see each other.

This article originally ran in Nature Alberta Magazine - Summer 2022.