Very colorful Gouldian finches
It turns out trying to find a mate isn't the main reason the plumage of many male birds are a lot more brilliant than those of females. The main reason is survival.
Researchers at the University of Wisconsin-Milwaukee compared male and female plumage in 970 species of birds. They noted the bright colors of birds are often attributed to sexual selection in males.
But researchers discovered that in many species, both sexes are equally colorful. So the question now was if sexual selection alone could explain the more brilliant plumage among males. The answer was no.
Researchers discovered that natural selection, or the survival of those more adaptable to change, played the major role in the males' brilliant plumage. They also found that although males often have more colorful feathers than females, both sexes are actually more similar than they are different.
That's because color affects things like avoiding predators and searching for food and is driven by both natural selection and sexual selection.
Researchers concluded that although most studies of bird plumage focus on dichromatism, or the existence of two colors, "evolutionary change has most often led to similar, rather than different, plumage in males and females. Our study shows that ecology and behavior are driving the color of both sexes, and it is not due to sexual selection".
"This should hopefully get researchers to think more about how color affects survival, especially predation and foraging success, in both sexes," said study author Peter Dunn in a report in the journal, Science.
