Monday, February 12, 2018

We'll Always Have Parrots

My significant other and I have two parrots, an African grey and a yellow-naped Amazon. They are 24 years old and very feisty--i.e., apt to bite fingers and toes.  They will also be around long after we have departed this Earth, for they live to be at least 55 or 60.  So that is why I have said "we'll always have parrots" in "parroty" of Rick in Casablanca.

And the parrots will always have colors: Yellow and green (with a white eye ring) for the Amazon, and various lightnesses of gray and red for the African grey.  But the colors may vary according to the aqueous environment: A grey feather immersed in water will stay grey but darken slightly. Orange, yellow,  and red will also hold their color in water. But green (and blue, I am told) will change. In particular, green turns brown when immersed in water.  Clearly there are at least two mechanisms for the color: diffraction/iridescence for colors that change on immersion in water (change of refractive environment), and conventional pigment reflectance for colors that don't change on exposure to water. For more on bird-feather color, see 

Many experiments are possible, including immersion of the whole bird. Sometimes I imagine I understand how Edgar Allan Poe could have been a bit freaked out by his raven because it was likely to outlive him. But, as Ilsa heard at that immortal moment in Casablanca, it is more likely that "we'll always have parrots."

Left to right: Alex and Poobah

Michael H. Brill

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