Cardinals are known for their bright red plumage, a color that gives birds an advantage when attracting mates. But what gives them this attractive hue?
It’s all in the genes, say scientists at Washington University in St. Louis.
In the journal Current Biology, researchers reported finding a gene that is activated in the skin and feathers of red birds. When red birds eat foods with yellow pigments, an enzyme linked to that gene converts those pigments to red.
Birds that have the gene need to consume lots of yellow pigments to develop that red plumage, said Joseph Corbo, a professor of immunology and pathology at Washington University.
Corbo said that could explain why red birds have more success finding mates.
"It's an indicator that they are otherwise healthy and getting a lot to eat," he said. "So that's an indication that they might be a good mate."
Red factor canaries have been around since the 1920s, when bird fanciers wanted canaries with red feathers. So they crossbred yellow canaries with the red siskin.
"We thought this would be a good entry point to understanding how red birds make red feathers," said Corbo, who compared the genomes of the three birds.
Scientists are studying more species of red birds to understand how the gene works.