What’s black and white and red and blue?

Two birds I saw on a walk.

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A Blue Jay on the lawn.

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Pileated Woodpecker in a tree, with moss and a climbing cactus.

The Cornell Lab Bird Academy: How Birds Make Colorful Feathers

As one might expect from the amazing diversity of colors and patterns exhibited by more than 10,000 bird species found in the world, birds can see color. The colors in the feathers of a bird are formed in two different ways, from either pigments or from light refraction caused by the structure of the feather.

A woodpecker’s brilliant red cap is formed by pigmentation of the feathers, but a blue jay’s feathers look blue because of the structure of the feather and the way it scatters incoming light.

If you find the feather of a Blue Jay or Steller’s Jay you can see for yourself how this works. First, observe the feather in normal lighting conditions and you will see the expected blue color. Next, try back-lighting the feather. When light is transmitted through the feather it will look brown. The blues are lost because the light is no longer being reflected back and the brown shows up because of the melanin in the feathers.

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