Earlier it was thought that male birds always have bright feather and due to this their evolution is more colorful than females, but it is not correct. According to researchers at the University of Wisconsin-Milwaukee, the color of the birds is driven by predation and foraging success.

Ever since Charles Darwin in the 19th century, researchers tried to find the difference between male and female birds. They focused on attributing the males' brighter colors to their need to attract females. The new findings have been published in the academic journal Science Advances.

To know about male and female birds, Linda Whittingham and Peter Dunn, professors of biological sciences at UW-Milwaukee, and Jessica Armenta, who teaches at Austin Community College in Texas, took different approaches. They worked on a theory which stated that evolution has resulted in similarities in male and female birds as much as differences.

During the study, the researchers considered more than 970 species of birds. They found that male birds had brighter colors. According to researchers, "Although most studies of bird plumage focus on dichromatism, 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".

According to Jessica Armenta, she has spent about four years to collect and examine data from 977 species of birds. During the research, she visited six museums in the United States and Australia. She looked at six birds of each species, three females and three males, according to Armenta.

To conduct the study, the researchers Whittingham and Dunn analyzed the data. They assigned every bird a color score based on the scales of brightness and shade. They also examined plumage color in relation to 10 measures of sexual and natural selection.