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BCA News: Fall 2018

Beware What Lurks Beneath

James T. Wetzel, PhD

Gulf Islands National Seashore forms an approximate 150-mile perimeter along coastal Alabama, Mississippi and the Florida panhandle. Along the Mississippi coastal region, tidal ocean waters mix with freshwater from the Davis Bayou watershed and provide both fresh and brackish water habitats that support a great number of indigenous plants and animals. This combination of aquatic habitats also attracts a wide variety of migratory bird species. Coupled with easy access along Mississippi Interstate 10, Gulf Islands National Park at Davis Bayou is well known as a fine area for nature photography.

On a July morning I arrived at one of my favorite spots – a small freshwater lagoon frequented by herons and egrets, hoping to better my collection of shorebird photos. What I found were two other photographers already in place, both in dentistry as it turned out, and who had not met one another before that morning. Both were similarly equipped – with lenses that likely cost more than my car, and that were nearly as long. Seeing no room to set up another tripod and with my 80-200mm ashamedly hiding in my pack, I decided to try an approach from the forested side, Black Needlerush.

Black Needlerush (aptly named) where burrowing chiggers are the norm, wading through all that brush brought me close to the water edge and a well shaded under an umbrella of Loblolly pine. Rough terrain but well worth the hike. Not 10 feet from the water edge was a partially submerged fallen pine. Hopping from bark to branch was a lovely Green Heron. The scene framed itself, and was wonderfully in reach of the 80-200mm.

I set up to take the shot, balancing glare, depth-of-field, and all the little things we do preceding the trigger of a shutter. Lost in composing through the finder, I heard what I could best be describing as a muffled grunt. Alongside the log and just outside my frame was a large female American alligator, Alligator mississippiensis, eyes just breaching the un-rippled surface. Wildlife biologists typically gauge the size of alligators by measuring the length between the medians of the nostrils to the med-point between the eyes. This measurement in inches is then converted to feet. I guesstimated this female to be approximately seven foot; perhaps more. And I state ‘female’ alligator based on a slightly more narrow snout than is typical of males, and the simple fact that the local ranger had told me earlier that her male counterpart in that same slough measures near twelve foot. Perhaps that will be next summer’s quest.

I assume she was submerged beside the log when I arrived, well color-blended and counter-shaded in the tannin stained waters and waiting in ambush for the perch of a bird or perhaps a nutria swimming by. Alligators have a unique method of ventilating the lungs, wherein the diaphragm is attached to the liver, and by using muscles that pull/push the liver, the lungs inflate without expansion of the rib cage. So, no ripples are produced to disrupt the water and ward off potential prey. Certainly I had not noticed her until distracted by the sound. She slowly submerged and resurfaced in the same spot repeatedly - long enough to allow me to shoot from several different angles, bracketing throughout, and making all the fine adjustments as needed for the shot I wanted. My favorite, of course, being when she was joined by an Eastern Amberwing dragonfly (Perithermis tenera) that settled just over the right eye. Soon after that final shot she submerged once again and did not reappear. The dragonfly found another (but far less photo-worthy) rest. As tempting as it was, I did not share the story with my friends across the pool.


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