“What’s often assumed is that sexual selection operates mainly on male appearance, and the result is that males then look different from females,” said Eaton. “Our results strongly suggest the opposite. Females, with their dull colors, are under strong natural selection to not stand out, thus they look very different from males. Perhaps this is because they spend more time on or near the nest and must be inconspicuous.”
Eaton also noted that the color differences in male and female birds go beyond what the human eye can see. “Our use of objective measurements of feather coloration, and quantification of color differences from the perspective of how birds see color differences, allowed us to uncover these complex evolutionary patterns that might otherwise go unnoticed,” he said.
The study, entitled “Reconstructing the Evolution of Sexual Dichromatism: Current Color Diversity Does Not Reflect Past Rates of Male and Female Change," is available online today in the journal Evolution.
Read the study: http://goo.gl/jyI4dy
- Sexually dimorphic Northern Cardinals: http://goo.gl/9ynLSf
- What can I feed the cardinals to make them redder? http://bit.ly/rAArXw
- What are the different types of cardinal birds? http://bit.ly/v0IBhS
- Northern Cardinal Fun Facts http://bit.ly/twE6NV