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Dramatic plumage -

The birds-of-paradise, which belong to the family Paradisaeidae, are best known for the dramatic plumage of their males.

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Long, elaborate feathers -

In many of the 45 species, the males have long, elaborate feathers that extend from the beak, wings, tail, or head.

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Very colorful -

Birds-of-paradise are also known for being vividly colorful. Many species have flamboyant hues of emerald, cobalt, and ruby in their feathers.

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New research -

Now, new research has revealed that birds-of-paradise may also be sending secret color signals to one another that are invisible to the human eye.

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The study -

A new study published in February 2025 discusses evidence of biofluorescence among various species of birds-of-paradise.

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Light from organisms -

Living organisms produce light in two key ways: bioluminescence and biofluorescence.

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Bioluminescence -

Bioluminescence requires a chemical reaction involving the molecules luciferin and luciferase. It is the light produced by fireflies, for example.

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Biofluorescence -

Biofluorescence, by contrast, is a phenomenon in which an organism absorbs light, transforms it, and then emits it as a different color.

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Decade of research -

Over the past decade, researchers have discovered biofluorescence in more than 500 marine species, ranging from sharks to corals.

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Biofluorescence in birds-of-paradise -

Thanks to a recent study, researchers have now been able to confirm that birds-of-paradise also produce light using biofluorescence.

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Method of communication -

With a reputation for engaging in elaborate courtship displays, scientists believe that birds-of-paradise may use these colors to communicate with one another.

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A majority -

The study was published in the journal Royal Society Open Science, and it describes biofluorescence in 37 of the 45 known birds-of-paradise species.

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The project's beginnings -

The project started around 10 years ago, when museum curator Dr. John Sparks identified biofluorescence across several fish species.

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Considering other species -

This led him to question how widespread this trait was among other species, and in particular among birds.

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Access to specimens -

As a curator in the department of ichthyology (a branch of zoology) at the American Museum of Natural History (AMNH) in New York City, Sparks had access to a vast array of bird specimens.

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Rapid survey -

He therefore conducted a rapid survey of the museum’s ornithology collection and discovered traces of biofluorescence in the birds-of-paradise.

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Digging deeper -

However, it wasn’t until Rene Martin joined the museum as a postdoctoral researcher in 2023 that the investigation went deeper.

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Revisiting the specimens -

Together with Sparks and Emily Carr, a doctoral student at the museum’s Richard Gilder Graduate School, Martin decided to revisit the birds-of-paradise specimens held at AMNH.

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Searching for evidence -

The team used high-powered blue flashlights and UV flashlights to look through the collection and search for evidence of biofluorescence.

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Special goggles -

As they searched, they wore special goggles that served to block the blue light and reveal only the illumination produced by biofluorescence.

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Taking pictures -

The specimens that were observed to produce light via biofluorescence were then taken into a lightless room to be photographed and have their light emissions measured.

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Findings -

Depending on the species, biofluorescence showed up in different body parts, including the birds’ bellies, chests, heads, and necks.

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Unexpected results -

Some species even had long, glowing plumes, gleaming bills, or glimmering spots inside of their mouths.

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Contrast with dark feathers -

In many cases, the areas of fluorescence were bordered by very dark pigmented feathers, which acted as a contrast against the light.

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Leading hypothesis -

As previously mentioned, scientists have hypothesized that birds-of-paradise may use biofluorescence as a means of communication or as part of a reproductive display.

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Aligns with existing knowledge -

This would align with the fact that male birds-of-paradise are known for engaging in elaborate displays when trying to court a female.

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Biofluorescence in other species -

However, there are other species of bird, such as owls, parrots, and penguins, that have been observed producing light via biofluorescence, but scientists are not sure why they do it.

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Could be a coincidence -

In some cases, experts suspect that biofluorescence may just be a coincidence and not serve any particular purpose at all.

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Looking ahead -

Going forward, scientists will continue to study biofluorescence, because it helps us understand how species have evolved to communicate.

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Exciting applications -

There is also potential for biofluorescence to contribute to medical and/or technological advancements.

Sources: (CNN) (AMNH)

See also: Meet the world's most poisonous animals

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