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Barn Owls: Masters of Camouflage Under Moonlight

A collaborative study by researchers specializing in biology and optics across various institutions in Spain has revealed that the distinct undercoating of barn owls enhances their stealth when hunting at night, particularly under moonlight and starlit conditions.

The findings, detailed in a paper published in the Proceedings of the National Academy of Sciences, explore how nocturnal light conditions affect the visibility of barn owls from the perspective of their prey, primarily small mammals such as rodents. The research team carried out comprehensive assessments to understand what characteristics might cloak the barn owl during its stealthy pursuits.

Unlike many owl species that showcase a range of feather colors aiding their camouflage in various environments, barn owls are notable for their striking white underbellies and round white faces. This color scheme, at first glance, seems advantageous for prey detection. However, the researchers questioned whether this unique coloration might actually help the owls blend into a clear night sky.

To investigate this, the team modeled light interactions across the sky, varying terrains, and the feathers of the barn owl. Their results highlighted that reflected moonlight renders the owls significantly less visible to creatures at ground level. On clear nights devoid of clouds, the similarity in reflectivity between the barn owl’s white underside—resembling both the moon and the night sky—created such low contrast that rodent prey struggled to notice the approaching predator. This camouflage allowed the barn owl to swoop down silently and effectively capture its quarry.

The researchers concluded that the coloration of the barn owl, particularly its white underbelly and round face, contributes significantly to its hunting success by making detection by prey exceedingly difficult until the last moment. Thus, the barn owl’s unique coloring is an effective adaptation for nighttime hunting.

More information:
Juan J. Negro et al, Nocturnal camouflage through background matching against moonlight, Proceedings of the National Academy of Sciences (2024). DOI: 10.1073/pnas.2406808121

Source
phys.org