Anhingadae, Anhinga anhinga


Family, genus and species.  The taxonomists were either suffering from an acute lack of imagination when they named and classified the Anhinga, or more likely they wanted to highlight the unique nature of this bird.  Anhinga, aka “Snake Bird”, “Darter”, “Water Turkey”, and “Devil Bird”.  This last moniker is derived from the Brazilian Tupi language word “ajina” which refers to a demonic spirit of the forest.

Female in flight

The Anhingadae family only contains a single genus, and that genus contains but one species, our Florida bird, in North and South America.  It does include three other Old World species, one each in Africa, India, and Australia/Asia.  Initially taxonomists thought the bird was closely related to cormorants, however newly discovered and unique characteristics have come to light.  This bird is the only bird, and probably the only vertebrate that has a single carotid artery (a great vessel extending from the heart to the brain).

Typical drying and warming pose

The Anhinga has an adaptation of the lower cervical spine that allows a rapid forward snap and recoil of the head and neck, effectively piercing underwater the tough side of the fish with its sharp bill.  The inside of the bill is lined with multiple barbs that tightly hold the flopping prey.

Riding low with small fish

This bird swims low in the water, propelled by webbed feet, with just the head and neck exposed.  Its diminished buoyancy is due to its dense bones, the ability to deflate its air sacs, and its unique feathers.  Anhingas lack the fine insulating feathers close to the skin which are found in cormorants.  Instead their feathers contain microscopic spaces that allow water to penetrate, making diving and underwater fishing easier.

The most common Anhinga pose is with wings widespread and drying in the tropical sun.  This also serves to warm the bird and overcome the disadvantages of its poor insulation.  You won’t find any Anhinga far from the tropics.

Female with catfish

I was birding in Eagle Lake Community Park, a local hotspot near Naples, with John, an enthusiastic novice birder.  A friendly couple from Detroit, (at least he was wearing a Tigers baseball cap) came up to us and asked, “what was that strange dark bird with the peculiar head?”  A quick check with the binos showed that the “head” was actually an unlucky sunfish impaled on the bill of a lucky Anhinga.

The dark bird with the peculiar head

As we watched the fish was beaten against a branch, I suppose to kill it.  The distracted snake bird did not notice a Great Egret lurking close by.  Just when the fish was ready for head-first swallowing the squawking egret pounced, wings spread wide, and the lunch was dropped back into the pond, satisfying no one.

Nesting Anhinga

The books say that these birds nest in diverse community rookeries, but I have seen them also nesting alone.  The males are entirely black and white while the females sport beautiful buff head and neck feathers.  Surprisingly you can also see these water birds soaring high in the thermals, often with the buzzards.  They’re the ones with the long fan-shaped tails.  Why are they way up there?  Its clearly not to locate fish.  Could it be purely for the joy of flying or is that explanation too anthropomorphic?  I’ll suggest it anyway until someone tells me something different.

A young Anhinga chick

I learned something birding with John this week. He reminded me of the genuine enthusiasm one has when seeing, actually seeing, a bird for the first time.  He had a set of new and decent binoculars and could now see the red and yellow epaulets of the Red-winged Blackbird and the golden eye of the Boat-tailed Grackle, both never noticed before.  Even at 60+ years it’s not too late to become a birder.

John also prompted me to call out the field marks, relative sizes, behavior, and songs of the common birds.  Specifically, how do you know its an “x” and not a “y”.  He and I were partners in a radiology practice up north and are not strangers to observing details and using pattern recognition techniques.  When an experienced radiologist first sees a chest x-ray he almost immediately knows if its normal or abnormal; no need to study the individual structures such as heart, lungs, bones, etc.  Your eyes and brain just know it’s normal.  And if it’s abnormal you also quickly know why; pneumonia, congestive heart failure, tumor, etc.

It’s only for the few rarities, both on chest x-rays and during birding, that one resorts to more careful observation of the specific “field marks”, goes to the books, or consults a colleague.  John and I have lived this routine in medicine for years and he, therefore, is perfectly suited to use the same technique in the field and become a seasoned birder.  First learn the specific field marks and behaviors of the birds and eventually your mind will ID the common birds subconsciously.

Lastly, John reminded me of the fun of birding with a novice. The Anhinga and the 30 some other common birds we saw that day were a great start. His excitement was contagious and the questions and banter were stimulating.  I thoroughly enjoyed the teaching; maybe it’s a new calling.

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