For years, scientists have puzzled over a feature that makes barn owls’ white plumage puzzling – shouldn’t it make them harder to approach their prey undetected? Researchers finally shed light on the mystery, suggesting that the owl’s brilliant white feathers are actually a form of nocturnal camouflage or counter-illumination.
According to lead author Juanjo Negro, the barn owl’s white underside effectively mimics moonlight, allowing its silhouette to blend into the night sky. This helps the hunter approach prey undetected, as the reflective feathers make it harder for mice or other rodents to spot the owl.
Previous research suggested that bright white coloration was a form of shock and awe, exploiting rodents’ aversion to bright light. However, Negro’s team found that this theory doesn’t explain the barn owl’s behavior. Instead, their new study reveals that the whiteness serves as nocturnal camouflage, allowing the owl to sneak up on its prey.
The researchers’ calculations show that the contrast between the reflective, white undersides of barn owls and wide areas of the illuminated night sky falls below the detection threshold of rodent visual acuity. This allows barn owls to approach their prey from a range of directions without being detected.
A similar phenomenon exists in the ocean, where fish often have light-colored undersides to match sunlit water and make them less visible to predators hovering below. Not all barn owls have white underbellies, however; some have reddish-brown plumage instead.
While one expert suggested that whiter barn owls might be more efficient hunters than their darker counterparts during a full moon, Negro’s team didn’t investigate hunting success in relation to plumage color. However, their findings add to the ongoing debate about the purpose of the barn owl’s striking white plumage.
The study’s authors and other experts acknowledge that there may be multiple explanations for the barn owl’s behavior, and further research is needed to fully understand this fascinating phenomenon.
Source: https://edition.cnn.com/2024/12/17/science/barn-owl-nocturnal-camouflage-moonlight/index.html