Birds of paradise send secret color signals that humans cannot see

Birds of paradise send secret color signals that humans cannot see

Many species of birds - including hummingbirds, peacocks and parrots - impress with their vibrant colors, but the Paradise birds particularly stand out with their shimmering tones of emerald green, lemon yellow, cobalt blue and ruby ​​black. Recent research now shows that these amazing birds also send secret color signals that are invisible to the human eye.

The fascinating biofluorescence of birds of paradise

The plumage and body parts of birds of paradise glow in certain areas when viewed under blue and ultraviolet (UV) light. They appear in light green and yellow tones. Scientists reported in a latest study published February 12 in the journal Royal Society Open Science was published about these exciting findings.

Biofluorescence: A unique phenomenon

Living organisms produce light in two ways: bioluminescence and biofluorescence. Bioluminescence, such as that produced by fireflies, requires a chemical reaction involving the molecules luciferin and luciferase. In contrast, biofluorescent creatures produce their light through structures that absorb high-energy light waves and then emit them at a lower wavelength.

Secret signals in the jungle

The researchers identified biofluorescence in 37 of the 45 known species of birds of paradise, which are found exclusively in remote tropical forests and woody habitats of Papua New Guinea, eastern Indonesia and parts of Australia. Under blue and UV light, these birds' white and bright yellow plumage emit colors that may be used in territorial disputes or when finding a mate, the study shows.

The special eyesight of birds

Birds are known for their exceptional color vision. Many species of birds – including pigeons, turkeys, ducks and geese – can be found in the UV spectrum see. However, little is known about the eyesight of birds of paradise. However, some closely related lineages, including the genus Corvus (crows and ravens) and the genus Rhipidura (fantails), are known to be sensitive to violet light waves react. For these birds, fluorescent markings would shine like a lighthouse in the dark, the study authors report.

A look at the dark side of color

Although birds of paradise are known for their dramatic colors, the biofluorescent aspect of their visual communication has been previously unexplored and raises new questions about how these birds use visual signals, says Dr. Rene Martin, the lead author of the study.

Research into the dazzling world of birds

It soon becomes clear that there are many more biofluorescent species than previously thought. Dr. John Sparks, a curator in the Department of Ichthyology at the American Museum of Natural History in New York City, identified biofluorescence in numerous fish species more than a decade ago. He has since questioned how widespread this trait is in other animals. Access to an extensive collection of bird specimens at the museum and a detailed examination with blue light finally confirmed his suspicions about birds of paradise.

A new light on evolution

The scientists took the birds into a lightless room, photographed them and measured their light emissions. Depending on the species, the fluorescence appeared on different parts of the body, such as bellies, breasts, heads and necks. Some birds had bright feathers, shimmering beaks, or glowing spots inside their mouths.

The importance of biofluorescence for science and technology

From the over 11,000 known bird species only a few groups show fluorescence. Some scientists suspect that birds of paradise and parrots use this ability for communication or reproductive displays. Studying biofluorescence is crucial to clarifying how different groups have evolved to communicate. These findings could also contribute to medical or technological advances.

It is very likely that if biofluorescence occurs in many life forms, it will have useful implications for the individuals who produce it.

Mindy Weisberger is a science journalist and media producer whose work has appeared in Live Science, Scientific American, and How It Works.