The silver feathers on an Anhinga's wings...or...baby's got bling!

When you seen Anhingas at a distance, they appear black, and you might not even know they carry a spectacular pattern of black and white (silver) feathers on their wings. When you're sitting right next to them, however, it's easy to see the "bling" on their backs...

A male Anhinga preening, showing off the striking pattern of black and silvery-white feathers on his wings.

This is the same Anhinga I talked about in two earlier posts that sat very close to me (click here for those close-up photos). Close viewing of the Anhinga's back let me study the beautiful pattern in his wing feathers (coverts and scapulars). I always thought these feathers were white, but up close, I could see they were silver...not white, not dull gray, but shiny silver!

The "white" covert and scapular feathers on an Anhinga are a glossy silver color. From a distance they appear white because of the contrast with the black feathers.

When I got home, I looked up Anhingas to see if they really did have glossy silver wing coverts and scapulars, or had I just imagined it. It turns out they do, and they owe their silver feathers to a special structure in the barbules of the feather. I found a detailed technical article published in the Journal of Morphology that explains why those feathers are indeed silver. Click here to read "Proximate Bases of Silver Color in Anhinga (Anhinga anhinga) Feathers," by Matthew D. Shawkey, Rafael Maia, and Liliana D'Alba.

...whether silver or white, the pattern on the back of an Anhinga is striking.

Bird feathers contain a center shaft called a rachis. Barbs branch off the rachis, and barbules branch off the barbs. The barbules run almost parallel with the rachis and hook together to make the feather strong.  The barbules in silver feathers are different--they are longer than those in other feathers, and they are flattened. Additionally, they twist a little, and one side is black and the other side is translucent. The twist means part of the translucent barbule is exposed, which creates the silver sheen. I found an article on the BBC Earth News site explaining the research of Dr. Ismael Galvan by Matt Walker called "Birds unveil 'silver wings'" (click here). This article is a little easier to understand than the technical research paper and clearly explains how the silver sheen appears on the feathers.

Galvan concluded that dark-colored birds evolved the silver sheen as a way to "become more colorful and conspicuous," while still keeping the benefits of dark-colored feathers (dark feathers contain the pigment melanin, which makes them stronger and protects the feathers from abrasion and UV radiation). 

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

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?"

A beautiful Anhinga looks over his shoulder at me while I photograph him.
"Yes, Mr. Anhinga. I'm getting it..."

An Anhinga sits in the spread-wing posture as he continues to dry his feathers. 

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.

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.

The sun shines through the wing feathers on an Anhinga (interior view) creating an amber glow.

...small feathers "standing on edge" make the upper part of this Anginga's wings look spiky.

"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

Anhinga closeups...

Anhingas are amazing birds—and very exotic to northern girls who don't get to see them up close very often. It's understandable then that I was stunned when this bird plopped down beside me as I sat near Lake Thomas in the Sea Pines Forest Preserve on Hilton Head Island. He had been drying his feathers on a branch sticking out of the water when I first saw him, but I wasn't paying much attention to him then. I had a map in front of me, and I was trying to figure out where a roost of Yellow-crowned Night Herons were. Suddenly, he made a gangly jump-flight and landed about 15-20 feet away from me, like he just wanted to drop in and say "Hello..."

Hello Mr. Anhinga. Charmed, I'm sure...

I really wanted to find the Yellow-crowned Night Heron roost, but adrenalin from the excitement of an unexpected encounter helped me focus my mind on the anhinga and soon washed away all thoughts of the night herons. I was more than happy to drop the map on the grass and just sit beside this incredibly cool bird. With his long, snaky neck and sharp dagger-like bill, it was hard to take my eyes off him...

The sky blue skin on an Anhinga's face is striking. I'm not normally close enough, however, to see it so clearly! This bird landed about 15-20 feet away from me as I was sitting beside the lake.

Anhingas lack oil glands, so they can't waterproof their feathers like ducks and other water birds. His scraggly, wet-dog-fur looking feathers definitely need some attention. A soft fluffy towel to dry off with would have been nice, but the sun and heat did the job just fine. 

He immediately struck up his famous feather-drying pose, and looked around. A few small bugs here buzzing near his face, and he'd shake his head now and then and snap at the tiny insects.

A male Anhinga hanging his feathers out to dry...

Why do Anhingas hold their wings open to dry their feathers?
You might already know about why these birds do not waterproof their feathers. If you don't, click here for a post I wrote last year on Anhingas that explains why waterlogged feathers help Anhingas by reducing their buoyancy so they can swim and fish under water.

...and if you haven't seen it yet, head over to 10,000 Birds to read Nate Swick's I and the Bird post on Cormorants, Anhingas and Darters.

An Anhinga snapping at flying insects from Kelly Riccetti on Vimeo.

I photographed this fellow on June 14, 2012 while we were on our vacation in Hilton Head, SC. It's about time I started posting some of the beautiful South Carolina birds we saw back then! Another post on this guy is in the works...

p.s. I never did find the Yellow-crowned Night Heron roost!

This is the first 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

An Anhinga sitting on a nest...

I almost missed this male Anhinga sitting on a nest. With his dark head held skyward, he bordered on invisible. You would think a big black and white bird would stand out in a sea of green leaves, but he didn't. His upward tilting head must have tricked my brain into thinking it was a branch and his dark feathers were shadows, but I was lucky because it was a hot day, and the fluttering of his gular pouch gave him away. The movement, made to help regulate his body temperature, was just enough to bring my eye back to his location....and there he was. Wow! My first nesting Anhinga at Pinckney Island...

An incredibly beautiful bird, this male Anhinga sat patiently on the nest incubating eggs. Males have mostly black body plumage. During the breeding season they develop a shaggy crest and mane, which are not apparent in this photo, but you can see the "filoplumes" on the sides of the face and neck. These feathers are silky and almost hairlike.

Anhingas are aquatic birds that do their hunting under the water. With their necks coiled back, they hold their bills open a little, so when they do strike with those sharp and pointed bills, they leave two puncture marks. After Anhingas eat, they climb up on a branch and open their water-logged wings to dry.

The ability of an Anhinga to strike out with lighting speed to impale its prey on its sharp bill while underwater is because of a hinge-like mechanism between the eight and ninth cervical vertebrae, and a keel on the underside between the fifth and seventh cervical vertebrae that muscles attach to. When this hinge-like mechanism is sprung, the muscles propel the bill forward like a spear being thrown (similar to herons and egrets). I wanted to see what this looked like and found a very cool drawing of a skeleton of an Anhinga's neck showing the muscles and hinge from 1913--click here for the drawing (sources: "National Geographic Reference Atlas to the Birds of North America," Mel Baughman, pg. 64--one of my favorite reference books, and a Wikipedia article on Darters, here.)

Note: The drawing of the Anhinga's spine is from "Die Vogel: Handbuch der Systematischen Ornithologie, Volume 1," by Anton Reichenow. Click here for a link to the book. If you speak German and like old pen and ink drawings, you'll like looking through the book.

A female Anhinga perches on a limb. Females and juveniles have buff-colored heads, necks and chests.

Look at those feet! I would never have guessed that Anhingas could climb trees, but they can. Their webbed feet are equipped with powerful claws that let them climb from the ground up to their nests. Anhingas build their nests over water, but not high in a tree. They like to keep them low enough so they can climb up into them. This nest was located about 15 feet off the ground. We don't have Anhingas here in Cincinnati. They are a strictly a southeastern bird, so I don't get to spend a lot of time watching them and had never seen one climb up a tree. Within two weeks of hatching, baby Anhingas can fall out of the nest into the water below them. To get back to their nest, they climb up the trunk using their claws (source: Baughman, pg. 65).

Water Turkey!

Because an Anhinga's tail feathers resemble a turkey's with a striped pattern and a pale tip, they've been given the nickname of Water Turkey (very fitting for this time of year...).

Hanging the feathers out to dry...

Anhingas, like Cormorants, do not apply waterproofing oils to their feathers to make them waterproof. Instead, the unprotected feathers absorb water, which allows them to stay submerged and swim easily under water.

Feathers that absorb water lose their insulating properties, which causes Anhingas and Cormorants to lose body heat, so when we see them hanging their feathers out to dry, they are also using the sun's heat to stabilize their body temperature. Most of us already knew this, but what I didn't know was Anhingas have a very low metabolic rate and become chilled easily. They are dependent on the sun's heat to ward of hypothermia. As a result, they can spend up to a third of their daylight hours sunning (much more than a cormorant). It also explains why we often see Double-crested Cormorants in Ohio, but almost never see Anhingas (I've never seen an Anhinga in Ohio). An Anhinga's normal territory is the subtropical southeast (source: Baughman, pg. 65).

Snakebird!

Since the Anhinga's feathers are not waterproof, when they get wet, they look shiny and very smooth. When you couple that with a submerged body, a long skinny neck, and a slim head, instead of looking like a bird in the water, it looks like a black snake swimming along, which leads to its second nickname, Snakebird!

I took these photos on June 8, 2011 at the Ibis Pond rookery on Pinckney Island NWR in Hilton Head, SC, except for the last photo, which I took on March 22, 2011 at the Ding Darling NWR.


Video of a male Anhinga sitting on a nest showing gular fluttering in the heat.

Tricolored Herons and an Anhinga at Pinckney Island NWR, SC

Birding on Hilton Head Island and Pinckney Island NWR…continued from Thursday’s post on the alligator.

On my second visit to Pinckney Island I was even more excited than the first. This time I knew what was there, and I also knew it was all good, so when I pulled off 278 and hit Happiness Way, exhilaration was what I was feeling. I couldn’t get to Ibis Pond fast enough and didn't even spend any time birding the parking lot area. On my first visit I had not seen any Tricolored Herons, so I assumed they weren’t nesting on the island, but what I didn’t know was I just hadn’t made it to their neighborhood yet. I started the day's trip by revisiting the Snowy Egrets and the Little Blue Herons (and checking for the alligator, who wasn’t there), and while I was standing there trying to decide should I go right or left, a Tricolored Heron coasted in over my head and landed about 20 feet to the right! (I LOVE this place!). I followed him over and found several Tricolored Herons hanging out together. Not too much squabbling, but every now and then a few males would let their presence be known with that funny, nasally moaning sound.

This sweet fellow led me directly to his nest and his mate.

These birds are gorgeous. They are so slim and trim, 

and their feathers are beautiful! 

Birdy bookends. In breeding season their bills are blue, but they

will fade to yellow as the end of the breeding season draws near.

The Tricolored Heron is the only dark heron with a white belly.

The little white topknot  feathers appear during 

breeding season. Such a stylish addition!

This little section of the island was home to a mix of Tricolored Herons, Little Blue Herons, Cattle Egrets, and of course, the ever-present Ibis. I wish I had written down a few more notes about this part of the island because I’m already starting to forget the little details, but I do remember one thing. With the click of that last photo, I backed right into a plant with lots of thorns -- small little razor-sharp thorns that ripped the skin as I tried to pull away and then stayed in the skin until I pulled them out. And…boy, oh boy did it bleed! Twenty-seven in all, at least they came out easily and didn’t hurt that much, but they left a big stinging sensation I didn’t like one bit. There’s nothing like seeing blood running down your leg to make you feel like a real birder. I hate to say it, but I kind of dug it, because it made me feel tough…like I was out in the wilds on my own surviving with just a compass and a camera. I had lens tissues in my little pack and after pulling out the thorns, used them with a little water to clean up the scratches. It seeped for a while, and I vaguely had thoughts of the possibility of poisonous thorns, but I soon forgot it as I noticed an Anhinga sitting on top of a tree. He was pretty far away (and the photos are poor), but I could still see the bare blue-green skin around his eye indicating he was in breeding season.

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