Monday, June 1, 2015
Muir Eaton of Drake University 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.
Eaton took readings of plumage color from 22 small spots on the body and calibrated readings for songbird vision (a wider span of the color spectrum stretching into the ultraviolet). The results add to a growing body of evidence that female coloration is more complex than the human eye can see.
Songs may also reveal similar sex-related twists in evolutionary history. Among temperate songbirds, males sing but females typically don’t. Yet a reconstruction of vocal differences between the sexes concluded that both males and females probably sang in the songbirds’ common ancestral species. Over time, it was the females that stopped.
The studies are available online:
“Reconstructing the Evolution of Sexual Dichromatism: Current Color Diversity Does Not Reflect Past Rates of Male and Female Change," in the journal Evolution: http://goo.gl/jyI4dy and "Female song is widespread and ancestral in songbirds" at: http://goo.gl/6Am4ND
- 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