Wednesday, February 08, 2017

It is Like a Sponge or a Box of Spaghetti

Today is the second day with temperatures in the warm 60s F.  In and off itself not a fact of global warming, but another chain in the link of a very mild winter which is another factual example (along with that YUGE breakin the ice shelf up North that is now 17 miles long.)  Yet this post is not about climate change.

I put out some bird feed in my bare feet on such a warm morning and then stood still for a minute or two and heard the song of the bluebirds just at the edge of the woods. Amazing. Singing! I am hoping they are not getting in the mating mood as we have many weeks of cold weather ahead. We are actually supposed to get snow tonight! 

Anyway, this got me thinking about bluebirds in specific and in general. Birds with yellow or red feathers get their pigment from food they eat.  Do bluebirds do the same?  Your first thought is blueberries, right?   But the science community says the blue color in blueberries is destroyed in the digestion process so the answer is "no".

So I did some reading.  I found the answer and while the reason is a bit complicated, my readers are intellectuals and love this stuff so I will share. Birds that have blue feathers in part or whole have changes in that colored feather itself as it grows. Inside each feather cell is stringy keratin molecules that separate from the water in the cell, something akin to oil and water. "When the cell dies, the water dries away and is replaced by air, leaving a structure of keratin protein interspersed with air pockets like a sponge or a box of spaghetti. When white light strikes the blue feather, the keratin pattern causes red and yellow wavelengths to cancel each other out, while blue wavelengths of the light reinforce and amplify"...and return to your eye as blue.

Difference in shapes and sizes of the air pockets mean different shades of blue. Therefore the color is not a pigment in the feather itself but a light reflection.

Why have the birds evolved this way?  Scientists don't really know but they theorize the bluest blue represents health to the female or perhaps just plain beauty.  OK.  You did not waste your time here today. You learned something new unless you already knew.

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