About the Photos

When I first learned that birds can see ultraviolet light, I was enticed by the possibility that they might have hidden patterns in their feathers that would be invisible to the human eye. I could hardly find any ultraviolet photos of birds. To satisfy my curiosity, I would have to spend about a year putting together a special camera system and get the photos myself. Now we can finally begin to answer the question, "What do birds look like, to other birds?".

Even though I was able to photograph birds using an ultraviolet camera, there is simply no way for the human eye to perceive the full range of colors that a bird can see. To display the photos, it was necessary to compress the broad spectrum of colors, perceived by birds, into the narrower spectrum perceived by the human eye. Something is lost, but at the same time we become able to appreciate some of the hidden colors that were previously known only to birds.

The first step is to squeeze all the colors of human vision into just the green-yellow-red part of the spectrum. Blue objects become green, and that frees up the blue part of the spectrum to be able to show the ultraviolet there.

1.	what humans see				colors reassigned				combined photo
2.	ultraviolet photo				ultraviolet assigned to blue

The ultraviolet photo is converted to blue. The blue picture is then added to the green-red picture, bringing it back to full color. Now the ultraviolet plays a role in shaping the colors in the photo.

On some web sites, you can find supposed examples of "bird vision", which are completely fabricated. It's good, they are at least teaching the concept that birds can see colors that humans can't see. But I wanted to produce images that actually correspond to what is captured by a bird's eye.

Ultraviolet adds a hidden dimension of color. Two objects can appear the same color to the human eye, but they will be two different colors to a bird. This project has provided a glimpse of what the world looks like to a bird, and it also allows us to appreciate the amazing variety of birds at a new level.

If you have any questions or would like to reproduce any of the images, for example on your web site, please send an email to .

© Nathan Chronister for permission