Rare Yellow Cardinals and White-Patched Mice

A rare yellow-feathered cardinal sits in an Alabama tree Feb. 17, 2018.
(Jeremy Black)

I. Several outlets (including the Chicago Tribune and Smithsonian magazine) recently reported on a rare bird sighting: a yellow male cardinal in Alabama. While females are generally more of a dull red or rust to the males' vibrant red, yellow coloration is abnormal for both sexes. Researchers suggest the bird's rare pigmentation may be due to a mutation in the CYP2J19 gene, which is responsible for red pigments in cardinals and other birds and insects (interestingly, the team that discovered this gene is also learning how birds create structural, not pigmented color). If not a mutation, the other hypothesis is that this cardinal is suffering from malnutrition and/or environmental stressors, which could impact the production of the color-converting enzymes... interesting that across species yellow is considered a signal of sickness (thinking jaundice, etc.).


II. I'm going to talk more about domestication later, but wanted to share this recent article in Science as it is also relevant to our pigmentation/coloration discussion. Here the authors show that wild mice living in a space relatively void of predators and with ample access to food and water became "tamer", and that with that increased tameness, white spots of fur emerged out of the traditional russet color. Over a period of six years the proportion of adult mice with white fur more than doubled. They claim this is significant because it occurred without human intervention, in other words, a case of self-domestication. I have issues with what they are claiming as "non-human" aided domestication, but still an interesting study.

-Courtney