Scientists Discovered That Owl Wings Glow Pink In Certain Lighting
The long-eared owl has tall ear tufts and a permanently startled expression that makes it look like it just overheard the juiciest piece of gossip in the forest.
They are dark-colored birds with black and brown patterning and distinct orange or yellow accents that allow them to blend into their surroundings.
But scientists have discovered that the owl’s feathered forest camouflage turns into a fluorescent pink color in certain lighting. Pink is definitely the last shade you would think an owl could be!
A team of researchers from Northern Michigan University and the state’s Whitefish Bird Point Observatory analyzed feathers collected from the inner wings of 99 long-eared owls during their migration through the Upper Peninsula in the spring of 2020.
They wanted to examine the various rosy hues on the wings of this population to see if they could figure out what the pink color might mean.
Owl eyes are able to detect the magenta fluorescence, which is emitted by photosensitive pigments called porphyrins, derived from the Greek word for purple.
They do not need the help of a UV light to see it. Other birds that can see in the ultraviolet spectrum can detect it as well.
Since the color is not visible to mammals, it could be a way for the owls to give signals to their peers without alerting their prey, which includes rodents and other small mammals.
The photosensitivity of porphyrins is what causes them to glow in the first place, but as they continue to be exposed to sunlight, that photosensitivity also makes them degrade over time. This means that avian fluorescence fades with age, as feathers molt.
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The researchers know that other pigments in bird feathers signal age, size, overall health, and more to potential mates and competitors.
For example, the color of long-eared owls’ plumage indicates whether an individual is male or female. However, the system is not entirely accurate because one-third of owls have a mix of coloring.
It is unclear if the owls’ pink glow communicates similar messages. The research team found feathers from older birds that had more of the fluorescent pigments than younger birds. In addition, the glow was stronger in the darker-colored females than in the light-colored males.
Younger and paler birds had stronger pigments if they were heavier, which could mean that the pigments are an indicator of an owl’s health.
“It is possible that fluorescent pigments exhibited in long-eared owls are used in [the selection of mates],” wrote the authors of the study. “The only time in which these pigments may be directly on display (besides during flight) would be during courtship behavior, during which the male performs a courtship flight to attract females.”
But this does not explain why the wings of females tend to be brighter. The team thinks heat regulation might be behind the difference in pigments. The fluorescent pigments in female owls’ inner wing feathers could help regulate heat and limit heat loss while nesting.
The study was published in The Wilson Journal of Ornithology.
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