Here in Southeast Arizona the vultures are congregating in vast wheeling kettles, presumably before migrating en masse to the warmer climes of Mexico and points farther south. At night they seek out favored trees, preferably lofty spreading trees such as cottonwoods.
Last week, near the house on Wood Canyon Road where I was staying temporarily, one of these vulture roost trees was nearby, and I often walked under it. Nearly always a stray vulture pinion or flight feather could be found, evidence of the jostling for position in the higher branches.
There is a descriptive nomenclature used by biologists to describe the various components of a feather. The main shaft terminating in the quill is known as the rachis, a word derived from an Ancient Greek word (ῥάχις) meaning “spine or ridge”. That same term is also used to refer to the main shaft of a compound leaf or a fern, a verbal expression of what could be called biological rhymes.
The smaller branches emanating from the rachis are known as barbs, and from the barbs radiate the familiar interlocking structures known as barbules. The latter two terms come from Latin words meaning “beard” and “little beard”, respectively.
Feathers are among the most complex integumentary structures in the animal world, but their wondrous details are most easily seen under magnification… or if somehow you could become smaller.
Here’s a thought and visualization experiment to try, just for fun:
Imagine that your body is shrinking and your weight has diminished to the point that you can soar effortlessly, like a mammalian insect. You drift down slowly over a vulture flight feather, buoyed hither and yon by tiny vagrant air currents:
You kick out your legs and find that you can direct your flight to some degree. As you glide over a landscape of geometrically-arranged barbules you marvel at their symmetry:
An undulating tree-like growth of down feathers near the quill-end of the rachis threatens to entangle you, and with a deft wriggle you narrowly avoid becoming ensnarled:
Suddenly, as you soar away from the feather, you notice a cat approaching stealthily. Time to assume your normal dimensions, wouldn’t you say?