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Wednesday, November 12, 2014

Nature struggles with the blues

Today National Public Radio aired a story about how difficult it is for organisms to make blue pigment. As it turns out, the vast majority of "blue" animals you may encounter are actually taking advantage of the prism effect, rather than having blue feathers, scales, and skin. A Steller's jay's blue feathers, when backlit, actually look black. The barbs of the feather are able to absorb every color except blue, which gets scattered back to the viewer. This is known as a "structural color." As it turns out, very few birds actually have the physiology to make blue pigments.

Click here for that story.


This got us thinking about all of the blue animals we encounter on Tejon Ranch- from western fence lizards (Scleporus occidentalis) to blue butterflies, to birds. In the wintertime, there are at least five species of birds that exhibit blue plumage by reflecting only the blue portion of the spectrum:

Mountain bluebird (Sialia currucoides)
Photo by Elaine R. Wilson, accessed from Wikimedia Commons http://commons.wikimedia.org/wiki/File:Mountain_Bluebird.jpg


 Western bluebird (Sialia mexicana)
Photo courtesy of Greg Smith, accessed from his Flickr account: https://www.flickr.com/photos/slobirdr/8304331232/in/set-72157603539054704


Western scrub-jay (Aphelocoma californica)

Photo courtesy of Chuck Noble

Note how different angles of light change the quality of the blue. Photo courtesy of Chuck Noble.

Photo by Ingrid Taylar. Accessed from Wikimedia Commons: http://commons.wikimedia.org/wiki/File:Western_Scrub_Jay.jpg

Steller's jay (Cyanocitta stelleri)

Photo courtesy of Chuck Noble

Photo by Outriggr on Wikimedia Commons: http://commons.wikimedia.org/wiki/File:Steller%27s_Jay.jpg




Pinyon jay (Gymnorhinus cyanocephalus)- Rare winter visitor based on pinyon pine production

Photo by US Fish and Wildlife Service. Accessed through Wikimedia Commons: http://commons.wikimedia.org/wiki/File:Gymnorhinus_cyanocephalus1.jpg
Photo courtesy of Chuck Noble

Blue Grosbeak (Passerina caerulea)- Not a winter bird, but striking nonetheless

Photo courtesy of Chuck Noble
 



If you're interested in learning more about bird feathers and structural colors in nature, consider following some of these links: