An extremely rare cardinal has birders and biologists flocking to Shelby County, Alabama this week, as images of a yellow cardinal have circulated around social media.More information at AL.com.
Auburn University biology professor Geoffrey Hill said the cardinal in the photos is an adult male in the same species as the common red cardinal, but carries a genetic mutation that causes what would normally be brilliant red feathers to be bright yellow instead...
Hill said that cardinals and other songbirds need to consume substances called carotenoids (found in sweet potatoes and carrots) from the environment around them to achieve their bright colors.
"Songbirds like cardinals almost never consume red pigments; rather they consume abundant yellow pigments," Hill said. "So, to be red, cardinals have to biochemically convert yellow pigments to red."