Bright bird plumage resulted from natural, sexual selection

Gouldian finch

Natural and sexual selection play a role in the color of a bird’s feathers, a new study finds. 

Peter Dunn

Charles Darwin observed birds such as the peacock and thought the bright colors of the male’s tail attracted females — an example of sexual selection. Alfred Russel Wallace suggested that duller female birds were the result of natural selection — bright colors stood out to predators as the birds protected their nests, so the birds that blended in to their surroundings survived.

Who was right?

A new study published March 27 in Science Advances suggests they both were. Scientists examined the colors of more than 900 species of birds, examining how much color differed between males and females and among different bird species. They showed that natural selection tends to produce similar colors in both sexes. But if the male is bright and the female dull, it’s primarily the result of sexual selection. Sexual selection may drive the sexes apart, but natural selection brings them together. 

Bethany was previously the staff writer at Science News for Students. She has a Ph.D. in physiology and pharmacology from Wake Forest University School of Medicine.

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