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Not all barn owls are snow-white. The color palette ranges from reddish-brown to white - with surprising consequences for hunting in the moonlight. (archive picture)
Keystone
It seems to contradict every rule of evolution: a predator that glows in the dark. But for the white barn owl, the lack of camouflage is not an evolutionary design flaw - it is its weapon.
This is shown by researchers from the University of Lausanne and the Swiss Ornithological Institute Sempach in a study published on Monday in the journal "Current Biology". "Conspicuous coloration in predators represents a paradox: High visibility should actually reduce hunting success, yet bright colors also occur in species that rely on inconspicuousness," the researchers write in the study.
To find out why this is the case, the researchers studied the barn owl. These birds, which are adapted to hunting silently in the dark, come in different color variations: From a dark reddish-brown to a brilliant white. This provides the researchers with a natural experiment: the same species can be used to compare how conspicuous and inconspicuous hunters perform under identical lighting conditions.
For their study, the researchers fitted 69 male barn owls with high-resolution sensors. The devices recorded flight movements, hunting attempts and prey catches over a total of 354 nights. This enabled the scientists to analyze more than 17,600 hunting attacks and, for the first time, understand in detail how differently colored owls hunt under different moonlight conditions.
A surprising pattern emerged: the brighter the night, the more the white owls adapted their behavior. They directed their attacks more frequently towards the moon, sought out open and illuminated areas and concentrated their hunting on the brightest phases of the night. Reddish-colored animals behaved much more cautiously and stayed in the shadows more often.
The success proved the white hunters right. They did not hit more often than their darker counterparts in individual attacks. Overall, however, they caught more mice on moonlit nights and needed less time to do so. The researchers suspect that the reflected moonlight on the bright plumage causes rodents to freeze for a brief moment. This moment could be enough for the silently approaching owl to strike.
The fact that a mouse sees the barn owl approaching becomes its problem.
08.06.2026, 17:00
