Light on Feathers

Black-billed Magpie, Montana

Black-billed Magpie, Montana. Visually looks likes half black and half blue.

Demonstrating the curious effect of light on feathers are these three photos of the black-billed magpie.


We came across magpies on a Montana back road, shown in the first two photos.  Athena captured the iridescent feathers on the wings and tail.


But often, as seen in the third photo taken by a different photographer, the bird shows no blue at all.  They look black and white.


Black-billed Magpie, Montana

Black-billed Magpie, Montana. Still some blue just above the tail, but mostly black.

Birds get their color in many different ways.


Some birds, like the flamingo, get their color from the food they eat.  They eat algae with beta-carotene and as a result, are a pink bird.  This kind of pigment coloring is common in many birds.


Black-billed Magpie (Idaho) in different light. Photo by Stephen S. Skrzydlo. Courtesy Wikipedia.

In other birds, however, the color comes from the structure of the feather and the surrounding light.  This is how the blue color is expressed in blue birds.


Light is refracted in the feather by a microscopic structure called a barbule or barb.   There are tiny air pockets in the barbules that capture and scatter incoming light.


In both blue- and iridescent-feathered birds, light is the determining factor for the color we see.  Bird photographers and birders are acutely aware of this distinction.


Image result for blue feather barbules diagram

Feather diagram courtesy


Anna's Hummingbird, Northern California

Anna’s Hummingbird, California. Throat gorget looks black.



Anna's hummingbird California. Same species, different light.

Anna’s hummingbird California. Same species, different light.

Likewise, sometimes we look at a hummingbird and the throat (gorget) looks black.  Then the bird turns slightly and you get a riot of color.


It is quite complicated, with varying wavelength refractions, differing species, etc.


You can read more about feathers here and here.  Hummingbird iridescence here.


Structural coloration is an often-studied concept  in nature for application to artificial or manufactured colors.  More here.


With some birds, everything in your perspective literally changes when more light is shed on the situation.  Another cool thing about birds.


Photo credit:  Athena Alexander unless otherwise noted

Image result for blue feather barbules diagram




73 thoughts on “Light on Feathers

  1. Wow, I never seen an Anna’s hummingbiRd with a purple head. The ones I usually see are green with a hint of red. Very nice photos.

  2. Interesting information on how birds get their coloring. I did know that with the flamenco it’s their shrimp diet. If that were true about people, I would be chocolate colored.

  3. Beautiful captures! Good to learn about the structure of feathers and lights that affect on colors.
    Anna’s hummingbird California is gorgeous. 🙂

    • Thanks for your kind words, Amy. Athena was excited about capturing that Anna’s h-bird on a wintry cold day when there was snow. I’m happy you enjoyed the post today~~

  4. Excellent informative post! And magpies are fascinating! I also find it very cool that many of the swatches of colors we see on birds are actually more brilliant in the UV spectrum. For example, the “purple” patches on the cheeks of budgies. They look purple to us in the visible light spectrum but are beacons of some color we cannot know in the UV spectrum. I like what I see in a fellow bird nerd, I’m happy to follow. If you’d like even more birds in your life, give my blog a look:

  5. Wonderful photos, especially the shots of the Anna’s Hummingbird. I am one of the people avian101 was referring to and your blog does provides a wealth of information for someone curious about birds. Thanks for sharing the great information about the light on feathers.

    • Ah, grackles are the perfect example of the magic of light, BJ. I love those boat-tailed grackles. We don’t have them here in no. Calif. but I love seeing them in various places when I travel. Once in AZ I wandered around in a fast food parking lot following some that were snagging snacks, I have no doubts I looked like a fool. lol. Thank you, as always, for your spirited visits.

  6. We have magpies that live in the trees near our yard. they are very sassy and think they own the place. A few weeks ago I went outside and a magpie was on the deck in the path i was walking. He made it very clear that he would not be moving. I’m going to have to watch them in the light for the blue. Ours definitely look black. I’ll let you know. I wonder if he would mind if I shone a flashlight on his feathers? Just for research purposes of course.

    • Hi Sue. Yes you have the black-billed magpie, as featured in today’s post. Interesting that you consider them black. Since they’ve become so cheeky in your backyard, there might be a day when you see the iridescent blue feathers, depending upon the light. They can be pretty bold, so I don’t think a flashlight will deter anything. How fun! Thanks so much, as always.

  7. I have sat watching pigeons and amazed at the different colors when the light hits them from various angles. Nature never ceases to amaze. Great shots.

  8. I can never quite believe or accept that a bird that looks demonstrably and unequivocally blue – say, an indigo bunting – is not in fact ‘blue’ at all. I’d like to know what its base color is! RH

  9. Another bird I’ve had a hard time catching with the lens, but they are very cheeky. I don’t see them around here though. Ducks are also fun with their changing color. Whatever would I do without color… it brightens my world. I’m having so much fun picking colors for the new/old house.

  10. Hello Jet! Aren’t feathers the most miraculous things? Not only are they cleverly designed for flight, but they are incredibly beautiful. The way light plays on them is magical. I think magpies and starlings are very beautiful. I love that their iridescence only comes out when the light hits their feathers just so. And I can certainly personally attest to the powerful pigmenting qualities of beta-carotene (as I learned from my carrot-juice-drinking days!).  As always, an informative and interesting post, Jet Enjoy the rest of your week! :))

    • Hi Jeannie, Oh so true about the endless beauties of feathers. One thing I have enjoyed about the comments on this post are all the dazzling creatures that friends have added to the list. Yes, swallows are another iridescent joy. My thanks to you and best wishes too.

  11. Fascinating information, Jet, thanks so much for sharing! I’m catching up on your posts, as always, they are truly informative and always interesting. You live an awesome life of travel! 🙂

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