Why is Tom’s Head Blue?
I don’t have the time that I did in early spring to quench my thirst for understanding of what’s going on around me so I won’t be so prolific on the blog until harvest is over.
Once the snow is off the ground the turkeys and chickens find all sorts of ways to escape or get into trouble like the adorable, chaotic toddlers they are. It can be frustrating and then they make you laugh, or fall asleep on your feet and you forgive them and are grateful for their childish trust in the almighty food and water and coop cleaner/provider person.
There was one fascinating thing that I learned about my new turkey friends that I thought I would share.
Tom has been quite the performer since the warm weather started, putting on a lovely show all day, every day for the girls and I. His snood (the funny nubbin that grows on the top of his head) extends and he turns the most lovely shade of blue to signal his interest in initiating the mating dance.
Shrunk snood, grew snood, red snood, blue snood.
A snood (rhymes with food) is an excellent indicator of a bird's emotions and health. When we first brought the turkeys home Tom’s snood was very pale and maybe only an inch or two long. Once he settled in I noticed that it was always quite long, six inches or more, and had reddened. At first I was worried he’d peck at it when eating or that it would freeze off because it was always dangling in the water when he went to get a drink and sometimes it was quite cold this winter. But his snood survived.
I’ve since learned that a long snood is a sign of a strong healthy bird. I know, it really does sound like we’re getting into whose is bigger territory but apparently: Measures of male ornamentation might be a culturally and economically feasible method of identifying conservation-worthy genotypes from indigenous poultry flocks. It may even help female birds with high coccidia infections to find a mate with more complementary genes.
Infected females did not invest more time assessing individuals, did not wait longer to choose a male, nor were they less likely to solicit during the trial. They did differ from control females in that they visited more males before soliciting copulation and exhibited different preference functions for snood length. These results suggest that females are not so energetically restricted by latent coccidia infection that they must hurry to find a mate. Instead, it appears that infected females assess a larger set of males as prospective mates, perhaps to increase the opportunity to obtain complementary genes for parasite resistance.
The bare skin also acts as his radiator to cool him down during his exertions in mating displays.
Understanding the color change
So long is strong, but why change color?
There is an incredibly sciency article I found about why they change color but it hurt my head trying to understand it. If this is your thing, please enjoy.
Biomimetics is a fascinating field whereby scientists look to nature to solve a problem or perfect a solution. To make an elegant solution.
The turkey snood and wattle have provided just such a solution. Berkeley scientists have used the turkey’s color changing adaptation to create a biosensor for germs, toxins, and TNT.
The turkey-inspired biosensors were exposed to a range of volatile organic compounds, including hexane, isopropyl alcohol and methanol, as well as TNT, at concentrations of 300 parts per billion. The researchers found that the viruses swelled rapidly, resulting in specific color patterns that served as “fingerprints” to distinguish the different chemicals tested.
Turkeys inspire smart-phone capable early warning systems for toxins
Why Blue?
Interestingly turkey’s wattles have a lot in common with the sky of all things.
The blood vessels on their face, snood and wattles are very close to the surface. This helps the “radiator” cool them down and is also why the face of a healthy bird will be bright red.
When they get excited the collagen fibers that crisscross their faces contract. This contracts the blood vessels causing them to swell and changes the way the light waves are scattered off the surface making us see blue.
Like light waves scattered in the sky make us see a blue sky, and yet when the sun sets and the light waves are scattered differently we can see all of the beautiful colors of the sunset.
We see all of these colors in the same sky because of the way that light bounces off the atmosphere and our eyes. Seeing sun rays shows us just how ‘light’ can travel carried by electromagentic waves.
Or like how a Blue Morpho butterfly can turn it’s “blue” on and off when flying in the jungle. I was able to watch one in the Amazon basin when I was in Bolivia as a teenager and it was so bright for a few flaps and then disappeared. A few seconds later it showed up again farther along in the jungle. I didn’t realize at first that the Morpho relies on iridescence to produce it’s color, not pigment. It was only when I had one in my hands that I understood how it’s color worked.
Blue Morpho butterly front (lower left) and back (lower right), and with the light from a window shining through it (top). Color refracts differently depending on the angle of light that hits our eyes.
The beauty of knowing
Children are best known for asking why, over and over and over again. They have such a desire to understand what is going on around them. Somehow we seem to lose that as we age. I can’t tell if it’s because we think we understand enough, or we’re just too busy and tired to learn anymore.
Josh just started a new project mapping habitats and he’s come to realize that longitude and latitude are not what they seem. Our version of a map that we learned in geography in school is wildly wrong. And yet, that’s what stays with us, even after we know it isn't’ true. Some people are petitioning Google to make a more accurate representation for maps. Life is wild!
So there’s my little bit of learning for the week. I can now connect Tom’s face to the sky to Blue Morpho butterflies. Isn’t it grand!
