This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Over the past 30 years, Swiss barn owls have become more reddish-brown and more heavily spotted. By analyzing the genomes of more than 3,000 birds, scientists at the University of Lausanne identified the genetic variants linked to these changes in plumage and revealed natural selection at work.
Their findings, published in Nature Communications, show that evolution can happen rapidly in the wild. From pure white to deep reddish-brown through all variations of golden brown, barn owl plumage varies remarkably from one bird to another. Some owls have only a few faint dark spots on their chest, while others display many more, much bolder markings.
Research at the University of Lausanne (Unil) has shown that these features are more than cosmetic. Plumage color is linked to fertility and hunting strategies, and therefore to diet. White barn owls, for example, use moonlight to their advantage when attacking prey.
Spotting, meanwhile, is associated with immunity and the ability to cope with stress. Birds with large black spots appear to withstand certain stressful conditions, such as food shortages or parasites, more successfully. This diversity is not fixed.
A study led by Tristan Cumer, a research fellow in the Department of Ecology and Evolution at Unil's Faculty of Biology and Medicine, on the team of professor Jérôme Goudet, shows that Swiss barn owls have gradually become more reddish-brown and more heavily spotted over the past 30 years. The findings were recently published in Nature Communications. "Drawing on the exceptional volume of data collected by Alexandre Roulin and his group, who have monitored these birds of prey in the field for decades, we were able to sequence the complete genomes of more than 3,000 owls and identify the DNA variants associated with color and spotting.
This is one of the most in-depth genetic analyses ever conducted on a wild population," says Goudet, last author of the study, also affiliated with the SIB Swiss Institute of Bioinformatics. The scientists pinpointed genetic regions that play a major role in the birds' appearance. These include MC1R, a gene already known to affect pigmentation, and a region on a sex chromosome whose contribution to color and spotting the researchers were able to clarify.
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