How Do Blue Jays Get Their Color? Blue Jays, also called Blue Magpies or Azulejos, are common songbirds that often visit the suburbs. The earliest taxonomists appropriately named these little birds Cyanocitta cristata, which means “blue chatterbox”. What the taxonomists did not know was that the tiles are not really blue.

The bright blue hue that distinguishes these little birds does not come from blue feathers, as you might think, but from a science trick, a kind of optical illusion, the same one that explains why the sky is blue.

How Do Blue Jays Get Their Color?

Structural Colors

Blue Jays structural colors

While a cardinal, for example, gets its red plumage from the red pigment, blue jays have no blue pigment. In fact, the blue pigment is rare in nature. Instead, the pigment (melanin) in the feathers of a blue jay is brown, but we perceive it as blue due to a phenomenon called light scattering.

The colors of the feathers are determined by pigments, called pigmented colors, or by light refraction, called structural colors. Feathers contain two types of pigments: melanins, which are highly delineated microscopic particles, which we see as black, opaque yellow, red, and brown, and lipochrome pigments, which diffuse into fat droplets and produce the colors yellow, red, and yellow. brighter oranges.

When light strikes a pigment, it absorbs all other wavelengths in the color spectrum, except for the color we see, which is reflected in our eyes. Black occurs when all color wavelengths are absorbed and no color is reflected.

The structural colors, produced by the selective reflection of light, are mainly blue, green, and violet. These brilliant iridescent colors are produced when light bounces off furrows and feather crests.

Optical Effect

Blue Jays Optical Effect

The distance between these surface irregularities influences the colors we see. These types of structural colors change with the viewing angle. But most blue structural colors are produced when smaller particles scatter light. These blues do not change hue when viewed from different angles.

In the late 1800s, British physicist John Tyndall first described how tiny particles, usually less than 0.6 microns, absorb the longest red wavelengths of light but reflect or scatter the shortest blue wavelengths. This phenomenon was known as “Tyndall scattering” and explains the blue color of the sky which is sometimes called “Tyndall blue”.

Tile feathers contain small air pockets and a protein called keratin. These pockets are so small that they fall into a group of tiny structures called nanostructures, which vary in size from microscopic to molecular. The tiny pockets are even smaller than the wavelength of visible light, which is exactly why the optical effect manifests itself.

Visible light hits the feathers and encounters the air nanostructures and keratin. The size of the nanostructure matches that of the wavelength of blue light. So, while all other colors pass through the pen, blue does not. It is reflected, so the blue color is seen.

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This optical illusion is not exclusive to blue jays. This same optical trick gives all bluebirds their brightly colored appearance, but none actually have blue feathers.