Skywatch: Mystery Clouds

Last week, before the onslaught of dense clouds and cold weather we've been having, I kept trying to capture a Colorado "true blue" sky. My timing was never right, as the best ones occur in morning hours, off to the northwest, while south and east tend to be more washed out.

Then this unusual formation caught my eye—several broad streaks radiating from an area to the east, behind the hogback, like faint streams of sediment in an otherwise clear stream. The only explanation I can offer is contrails, spread laterally by winds aloft, or what, according to Wikipedia, would be called decaying contrails. This is suggested by comparison with the relatively coherent trail to the right.



A sky without contrails, or artificial clouds, would have been standard not so very long ago. Here's a better view of the hogback, one of my all-time-favorite geographic features, showing the west, or scarp, face of the Dakota Group sandstones that create the ridge.

Posted for Skywatch Friday, where many more skies await you.

Life is Metallic

  Life Photo Meme is a weekly challenge
  to post a photo of something alive that
  meets a certain criterion, giving us an
  opportunity to think outside our normal
  posting topics and, often, learn something new! Metallic, this week's prompt, is easier to find in beetles than in plants! I've always admired that color I call "bug green," that was popular in cars a few years back.

Today, we'll venture into birds, where metallic plumage is an accessible option. It turns out there are three basic techniques birds use to create the display colors we appreciate especially during breeding season each year: pigment-based colors, structural colors, and cosmetic colors. Among the pigments, carotenoids produce yellow, orange, and red (as they often do in butterflies, flowers, and, well, carrots); melanins produce browns, blacks, and grey, not too spectacular sometimes, but forming the background against which the showier colors are displayed.

Melanins are also critically involved in the production of structural colors, serving as layers in thin-film reflectors or to absorb incoherently backscattered light from reflective keratin and air matrices (Prum 1999, as cited in Shawkey & Hill, 2005). Nano-scale reflective tissues, they add, usually produce UV-blue, white or iridescent coloration.

I thought sure the Black-billed Magpie above would be happy to demonstrate, but he only looks blue. He/she posed in the sun this a.m., giving a little better show.

Because his/her normal magpie iridescence was not adequately displayed in these photos, I turned to a feather source nearer at hand, if less exciting: our mixed-breed flock of domestic poultry. Beaks, here, being a Black Australorp rooster, was willing, and iridescence, or metallic hues, does seem to be best displayed in black feathers. Even this close-up can't do justice to the structural colors created by the intricate design of feathers. George refused to come out from under the juniper to pose, but I wish you could see his iridescence, not confined to blue-green, but venturing into mahogany and rust.

Here's a Partridge Rock hen, capturing a little of the mahogany color George displays so well, along with the traditional iridescence, all against the melanin background feather pattern, somewhat more subdued.

For comparison, a Buff Orpington hen demonstrates complete lack of metallic iridescence. According to Shawkey & Hill, some carotenoid displays (notably in the American goldfinch), though pigment based, depend upon white structural tissue to achieve the brilliance we expect in their vivid yellow.

And cosmetics? As we might expect, they are substances (from oil glands or soil, e.g., iron oxides) externally applied by birds to their feathers, to boost their appearance and attractiveness to potential mates. Parrots and pigeons, among others, use this approach.

All these techniques for creating display colors in birds have a metabolic cost, and must also have an adaptive advantage as payback, without which our world would be less metallic and far more drab.

——
Shawkey, Matthew D. and Geoffrey E. Hill. 2005. Carotenoids need
structural colours to shine. Biol. Lett. 1, 121–124; doi:10.1098/rsbl.2004.0289 Published online 16 May 2005.

Your assignment, should you choose...

Yesterday I had a surprise note from a stranger: Arj at Science on Tap. Seems he's launching another blog meme and tagged me to contribute a list of "half-dozen-or-so books you would recommend every young person read by the end of their school years to help them maintain a sense of connection to, and value in, the natural world." (I don't know, Arj, isn't this a little personal?)

I've been browsing around in Arj's blog, brand new this year, and it looks like a pretty cool place to hang out. I especially recommend his post featuring a zoom video of a Mandelbrot set! Comes with its own music, an ode to Mandelbrot himself.

What's the blog world coming to? I was happy just snagging a Fractal of the Day once in a while, and now we can zoom M-sets on You Tube! (Today's fractal is nice, but yesterday's was blue! Even better...)

You can scroll down for some Strange Attractors too. Sprott's daily fractals now come with their own fractal music even. Isn't the internet wonderful?

Oh dear, was I procrastinating? Guess I'd better get back to business. Six books. Must-read books. That's tough, narrowing it down, so I'm offering a few more for those of you who want extra credit. Okay, here's what I came up with, in no particular (but definitely not random) order:

• The Living Landscape, by Paul B. Sears, 1962
  Ecological literacy at its first and best, a whirlwind tour of "everything you need to know about" your ecosystem, right down to its geological foundations, in a scant and readable 170 pages or so.
  (Extra credit: read his 1935 classic, Deserts on the March, which actually launched the environmental movement but didn't get the credit.)
  
  
• Sand County Almanac, by Aldo Leopold, 1949
  (This is the one that got the credit. Much as I love it, I'd hate to include it here if it bumped a lesser known book, but we won't let that happen.)
  
  
• Desert Solitaire, by Edward Abbey, 1968
  The protestors and innocent bystanders were getting tear-gassed at the DNC in Chicago or shot at Kent State, but Abbey was on a fire lookout tower in Arizona writing this book. Don't miss it!
  (Extra credit: The Journey Home, 1977. Granted it focuses on the American West, both of these do, but there's no reason Arj's mythical "every young person" shouldn't understand the American West. Sorry, no hall passes on this one.)
  
  
• Person/Planet, by Theodore Roszak, 1979
  This gentle but uncompromising book convinced me, a lifelong misanthropist, that there was a causal relationship between human problems and the concerns of planetary ecology, and that's a tough sell. Roszak is a sociologist and philosopher, but I adore him anyway!
  (Extra credit: His 1968 Where the Wasteland Ends, the world's best-ever critique of science, which almost derailed my thesis when I read it in 1973.)
  
  
• The Revenge of Gaia, by James Lovelock, 2006
  Aha! This one's on my nightstand now, and that makes me (and Lovelock) look almost up-to-date in the world! If you believe in global climate change, you should be reading this book. Or at least a few of my comments on it.
  
  
• Deep Ecology, by Bill Devall and George Sessions, 1985
  For bringing Naess' work to light, giving us words like ecocentric, and helping us see our human bias and our blindness toward Nature, this thought-provoking book is well worth a read.
  

Book reports are due Monday! Get busy, people!

Good grief! I seem to have left out Loren Eiseley, Joseph Wood Krutch, Hal Borland, Paul Ehrlich, J. Frank Dobie, Wendell Berry, William Least Heat Moon, Robinson Jeffers, Konrad Lorenz, Lewis Thomas, May Watts, Verlyn Klinkenborg, and... well, you see where this is going.

Lastly, on this impossible assignment, I'm tagging:

Fred, at Fragments from Floyd
The Watcher, at Watching the World Wake Up
Dave, at Plummer's Hollow (or Via Negativa, his choice)
William, at A Sylvan Dream (if he's back to writing)
Dave, at Osage + Orange

——
Guess all this reveals my formative period. But actually, I didn't read Sears' books until I got interested in him as a research subject, circa late 2005. They, like the others on this list, hold up well despite their age and I recommend them anyway.

Having trouble finding them? Visit Alibris—there are worse ways to lose your paycheck!