Showing posts with label Spread-wing posture. Show all posts
Showing posts with label Spread-wing posture. Show all posts

Sunday, December 16, 2012

More Anhinga photos; spread-wing posture and feather closeups...

...continued from the previous post, Anhinga closeups: those crazy Anhingas.
If you read the previous post, you know this bird came very close to where I was sitting and started drying out his feathers. Originally he was sunning himself on a branch in the water, then hopped on shore near me. After a while he returned to the branch. If I didn't know better, I'd think he wanted to make sure I could photograph all of him instead of just the closeups of his face. His look back at me seems to say, "Are you getting this?"

An Anhinga perched on a branch in the spread-wing posture sunning himself.
A beautiful Anhinga looks over his shoulder at me while I photograph him.
"Yes, Mr. Anhinga. I'm getting it..."

An Anhinga sun bathes while he dries his feathers. He's on a branch in Lake Thomas on HHI.
An Anhinga sits in the spread-wing posture as he continues to dry his feathers. 

...even when dry, an Anhinga will sit in the sun with wings spread to capture the sun's warm rays.
Anhingas sit in the sun with their wings spread even when they are dry because they also use this posture for thermoregulation. 
Anhingas and cormorants both use this posture to dry their feathers, but Anhingas rely on the posture to help keep them warm too. Anhingas have low metabolic rates and high rates of heat loss from their bodies. This is why you don't find many Anhingas up north. They need the sun's warming rays to survive. According to Stanford University (click here for the article), dry Anhingas use the spread-wing posture when the ambient temperature is cool but the sun is shining brightly. They sit with their backs to the sun for optimum heat absorption. Why don't cormorants do this? Because they don't have to. Their feather structure is different. Although both have "wettable" feathers allowing them to lose buoyancy so they can dive and swim under the water to hunt for fish, only the outer part of a Cormorant's feathers becomes waterlogged. This creates an insulating layer of air next to the skin when the bird is under water.

Closeup of an Anhinga's feathers.
Anhinga's feathers become wet all the way to the skin. Anihingas use the muscles in their skin to make the feathers stand on end to help them dry.

Closeup of the interior of an Anhinga's wing...the sun is shining through feathers.
The sun shines through the wing feathers on an Anhinga (interior view) creating an amber glow.

Close-up photo of an Anhinga's feathers. The small feathers on top look spiky because the muscles are holding them up on edge, to help them dry.
...small feathers "standing on edge" make the upper part of this Anginga's wings look spiky.

Water Turkey and Snakebird are two common nicknames of the Anhinga.
"Water Turkey" is one of an Anhinga's nicknames. It's easy to see its origin...the striped pattern and light tips on a spread Anhinga's tail resemble a turkey's. It's other nickname, "Snakebird," is easy to figure out too. When an Anhinga's body is submerged and only its shiny, wet head and neck are visible above the water, it looks like a black snake swimming along (click here for a photo in a previous post).

...I have another post on this fellow in the works. It focuses on the beautiful pattern of white feathers on the back of an Anhinga's wings. I photographed this bird on June 14, 2012 while we were on our vacation in Hilton Head, SC. I was sitting on the bank of Lake Thomas in the Sea Pines Forest Preserve on Hilton Head Island.

This is the second of three Anhinga posts:
Part 1: Anhinga close-ups
Part 2: More Anhinga photos; spread-wing posture
Part 3: The silver feathers on an Anhinga's wings

Monday, April 20, 2009

Turkey Vultures raising and spreading their wings in the sun...

Just before dinner, I went out on our balcony at the Clifty Inn and saw these three Turkey Vultures just hanging out around the fire pit. The scene took me by surprise and was sort of comical. To see these huge birds walking around on the ground, preening now and then, and basically acting cool, was like looking over the fence in the Munster's back yard!


Dude, what's for dinner?


This is the reason you always use a tablecloth in TV country...

The sun was out, but just barely. It was mostly under a cloud, but suddenly, the cloud cover broke and the sun burst forth at full strength. Like a choreographed dance, the three birds immediately turned around so their backs were to the sun and lifted their wings...at the same time and in the same way. 


...very cool to watch, but sort of creepy too! It looks 
like there is something really important in the fire pit...


I was focused on the middle bird, and after I clicked my 
camera, he turned his head around an looked at me. 
I wonder if he was the same one giving me the eye in 
the previous flight photos?

Beak Bit
It was fun to watch the vultures because as soon as the sun would go back under a cloud, they would drop their wings, turn around and start preening or walking around. Then again, as the sun came out, they would turn their backs and lift and spread their wings, fully extended. Matty wondered what they were doing, and I know other birds will use the sun to heat up parasites (mites) in their feathers to kill them, so I assumed the vultures were doing the same thing. Last night I did a little research and found, yes, they use the sun to kill parasites (or to heat up the mites to get them to move so they could be more easily preened off), but they also raise or spread their wings for other reasons.

To kill the bacteria that coats their wings after eating carrion. After the Turkey Vultures eat, they are often covered with nasty bacteria from their decaying meal. The sun's ultraviolet rays effectively kill the bacteria on the wings. Turkey vultures can eat decaying and contaminated meat because of enzymes and bacteria in their digestive systems. As a means of defense, Turkey Vultures will projectile vomit just like Great Blue Herons. Throwing up fish is one thing, but throwing up rotten, decayed and contaminated meat is another. Yuck!

To warm themselves on cold mornings. Turkey vultures can lower their body temp to conserve energy at night, but in the morning, they need to warm up to be able to fly. The outstretched wings absorb the heat from the solar energy and soon warm up enough to take off. When the TVs take off, they use their incredible sense of smell to detect carrion. Turkey Vultures can even find natural gas leaks because the additive to the normally odorless gas (ethyl mercaptan) is a chemical similar to the one let off by decaying meat.  


Turkey vultures eat mostly carrion and therefore do Mother Nature a great service. Their feet and beaks are weak, and they can't carry food like a raptor or kill like one. Their cousins, the Black Vulture have stronger beaks, and sometimes kill food. Turkey Vultures never circle a dying animal. They circle and ride thermals, and seek dead things by picking up the odor.

For close-ups of a Turkey Vulture, click here