What makes the male Rose-breasted Grosbeak's red breast - red - rather suddenly became a matter of much curiosity for me.
I had turned on the camera video feed as I sat down with my morning coffee. A Grosbeak was on the tray feeder when it hit me -- his chest was pure white.
The camera was still in night infra-red mode (black and white), but I would expect to see at least a grey splotch where the red is supposed to be. Could I have another Grosbeak with a color aberration?
Moments later, the camera switched into daylight mode. The Grosbeak's red breast lit up. I would love to tell you why, but I don't know, nor could I find any articles giving me a definitive answer. Someone who knows more about infra-red may be able to say it is about the Grosbeak's exact color of red and the technical qualities of IR light. The other possibility is that the Grosbeak falls among the many birds whose color is not actually due to pigment. Birds in this group get their color from the structure of their feathers and how these feathers reflect light. Bluebirds are an example. They appear blue to us because of how the structure of their feathers reflect light.
I'm going to reach out to Cornell Lab or Ornithology for an answer on the Grosbeak. When I get an answer, I'll add it to the comments of this post.
Here's the color transformation captured on video ...