Saturday, June 27, 2009

Zipping up a Feather







There’s a whole lot of moulting going on at the moment in the bird world, as they begin to shed their well-worn breeding plumage. My wife found this distinctive feather on our garden path last week. Under the microscope the underside of the feather (top photo) reveals the beautiful repeated pattern of rows of barbs attached to the central shaft (rachis). At higher magnification (second photo down) you can see the rows of barbules on each barb, each ending in a tiny hook (barbicel). When a bird preens a feather by drawing it through its beak, it’s zipping these rows of hooks on adjacent barbules back together again, to restore the feather’s aerodynamic efficiency. In the bottom two photographs the feather has been flipped over to view the upper surface and reveal a clue to its identity – the blue iridescence in some of the barbules. It belonged to a magpie.

8 comments:

  1. We think man is ingenious inventing things like the zip and velcro but in reality similar mechanisms were evolved millions of years ago.

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  2. Marvellous architecture revealed there, Phil. The top photo reminds me of the roof structure of a London railway station but I can't recall which one.

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  3. Hello Greenfingers,

    Your posts are a real treat. I really appreciate the fine quality of your photography and the details you provide about the subject matter. I hope you don't mind that I added a link to your blog on my blog.

    cheers,
    Wilma

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  4. Thanks for visiting and for your kind comments, Wilma - and for making the link.

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  5. Hi Rob., I know what you mean...but I can't recall which station it is either.

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  6. Totally agree, John, there's a long list of human inventions that mimic nature.

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  7. Stunning photographs. Iridescence is such a fascinating topic, too. I remember being awed by the fact that much of the Kingfisher's apparent 'colour' is the result of iridescence.

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  8. Hi Caroline, you find it in usual places too - in polychaete worms, for example - notably in the 'sea mouse'

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