Feathers – textures, patterns and growth

 

Coppery Aigrettes of the Tri-color Egret

A spray of coppery plumes (aigrettes) lit by the sun and contrasted with the slate blue contour feathers and white body feathers of my favourite diminutive heron…the Louisiana Heron (Egretta tricolor).

Great Blue Heron Chick in Sunning Posture - Young Wings with Blue Quill feather growth

Ever since my first view of the young wings of a Great Blue Heron chick I have been fascinated with the way they grow and that interesting parallel arrangement of the pretty blue sheaths from which the feathers emerge. They always remind me of an Indian headdress in design. So I thought this view deserved some explanation!

A bird’s wing is very similar in its skeletal structure to a human arm and is, in fact, a modified limb. If you keep your upper arms to your sides, rotate your forearm sideways away from your body at the elbow, then tilt your hand down at the wrist with your thumb up, that is pretty much what you see in the picture above of the juvenile great blue heron standing with wings lowered and tilted towards the sun (sunning posture). The blue sheaths you see on this young bird house the growing flight feathers. From the ‘forearm’ section grow the secondary flight feathers and from the ‘hand’ section grow the primaries. From the ‘thumb bone’ grow the feathers of the leading edge of the wing called the alula. You can see this in the above image as well.

Feathers grow from papillae or follicles (like bumps) arranged along the birds skin in traces called ‘feather tracts.’ Each of these follicles is supplied with a vein and an artery. The outermost layer of the papilla forms a protective sheath inside which a feather grows, tip first, outwards. These new structures are called ‘pin feathers’ for their straight and pointy appearance. They are also called’ blood feather’s at this stage of growth due to the venous and arterial supply while growing which will bleed if plucked or broken. Ultimately the sheath splits and falls off allowing the tightly bound feather to unfurl. Once the feather is fully grown the papilla recedes and dries up leaving a hollow shaft. The feather is not ‘alive’ at this point not needing a blood supply, although the follicle itself does keep a blood supply in the skin. The tip is the oldest part of the feather and the base the youngest.

A chick like this one is growing new feathers all at once, and so there are lot of pin feathers. Later on as feathers become worn out new ones will grow to replace them.  Sometimes when you see a bird preening it is to get rid of insects or parasites, but also the sheaths do not always fall off so easily. I am sure many times when I see birds flicking their beaks out along the feathers that they are pulling sheaths from new growths away. I understand at times they will do this for each other.

In between the blue sheaths you can see other pin feathers sheathed in white for other feather layers. Right now the wing or arm of the bird looks rather like an anatomical drawing as there is not much there but skin, muscle, bone, ligaments and young feathers. When fully feathered these wings will become beautiful and inspire the awe that birds always do when soaring. Our arms so similar and yet we can only dream of flying!!

Dove Wing

This illustration of a dove’s wing shows the wing bones and how the secondary feathers relate to the radius and ulna of the’ forearm’ and the primaries extend from the’ hand’ bones. Alula feathers you see attached to the ‘thumb’ at the leading edge of the wing.

Below are the context shots of the nesting Louisiana Heron and the Great Blue Heron Chick.

Tri-color Egret at its nest-alarmed by an intruder

Great Blue Heron Chick--Sunning Posture with young wings-displaying blue quills with feather growth

I find the patterns of nature fascinating and beautiful. Natural forms, patterns and textures inspire everything from art to architecture to the clothes we wear!

I did want to share the link to the blog of a wonderful and nationally acclaimed sculptress – Sandy Scott.  She specializes in sculpture and sketches of wildlife, especially birds. She has several posts on the anatomy of birds and bird wings with her own very clear drawings which she uses to teach how to accurately draw or sculpt them. Discovering her work was a treat for me so thought I’d share something found while learning more on this subject.

Judy

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~ by Judy on April 3, 2014.

10 Responses to “Feathers – textures, patterns and growth”

  1. Thanks for the anatomy lesson. And when I’m up with insomnia at 5 AM, I appreciated the pictures a bit more than usual.

    • I am happy for the appreciation while sorry for the insomnia! My insomnia seems to be early as in can’t get to sleep, but once I finally do usually am hard asleep at 5AM. But, maybe it is a good thing. I’ve read that if you want to be a writer while employed elsewhere, one must fall in love with 5AM. No distractions from the characters clamoring to be heard!!

      Glad you liked the anatomy lesson!! I thought those blue sheaths needed some elucidation!!

  2. Great shots and very informative post about feathers. Thanks, Judy.

    • No problem!! Thank you for reading my missive and commenting!! I did only skim the surface of info on feathers though as there are quite a few kinds from the contour body feathers, down, powder down and various kinds of plumes!! So very interesting really. Seeing young birds really does give a good visual of the growth pattern.

  3. These are truly beautiful photos, Judy! The first photo in particular is just stunning, with such amazing detail! How in the world do you get that close? You are so blessed to live in such a beautiful place with such beautiful birds. I look forward to your future posts!

    • I am particularly happy to hear that you liked the first picture. I debated a lot on the cropping and what to show of the spray of aigrettes and rich textures/colors of the other feathers. I am truly blessed to live close to a nesting colony and get close to the birds and in a way which is not harmful to their activities…being accustomed to human visitors.

      This year has been so strange in that some of the further out trees islands were cleared out of foliage. I think this caused many egrets and wood storks to relocate within the wetland and nest in different areas which were much closer. In some cases crazy close.

      The spray of aigrettes is a crop though. Soon I look forward to posting images from last Sunday of a nesting Louisiana Heron aka Tricolor. And the same pond apple tree had a pair of Glossy ibis nesting as well. Have never been close to one of those nests before.

      I do love the nesting season.

  4. What a beautiful, fascinating post… The feather detail is simply mesmerizing. I’ve always been fascinated by the details, and you’ve captured it beautifully. Wonderful article!

    • It is such an interesting growth process and so much detail with all the kinds of specialized feathers different birds have. Birds can move the feathers as the quill in the skin is attached to muscles rather like the bristling of animal hairs. So birds can ruffle them or raise them when excited to show off or position them for flight. I’ve read that feathers also have a nerve and so can be sensitive organs of touch. So I only scratched the surface of the complexity of these amazing structures. I had been curious about the blue sheaths and pin feathers for some time.

      Thanks for finding it interesting and informative. Great fun!!

  5. From a purely artistic standpoint, I do prefer that first photo. But who could resist that full view of the nesting Louisiana Heron? My gosh — she looks like she’s put on her best clothes to sit on the nest!

    The details about the feathers are fascinating. After a lifetime of hearing about pin feathers, now I understand them. I’m not sure I got my arm twisted around the right way, but no matter. What tickled me is that I’ve always though of the outer wing feathers of pelicans as fingertips. When they glide close, only inches off the water, you can see those tiny, incremental movements, as though they’re “feeling” their way along. Just amazing.

    • Yep, she’s all dressed up in her mating apparel!! After the eggs hatch and chicks are growing those aigrettes and the fancy white crest plumes along with the red legs and blue lores will slowly fade to its everyday clothes!!

      I can see what you mean about the Pelican fingers…and so very close to reality!!

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