The Terning of the Tide

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Courting Sandwich Terns

Nature is a magical thing.  The lives of plants and animals are filled with beauty, drama, failures and triumphs, terror, violence, and tenderness.  Capturing these candid interactions on camera is a dream for any nature photographer.  But it is no easy task.  Doing so requires that the subjects accept you into their world, and most species are reluctant to do so.  There are those special times, however, when patience and persistence pays off, and the determined photographer is rewarded with a rare glimpse of the intimate beauty of nature.

I had one such opportunity recently, when a business trip to Galveston corresponded with the tail end of migration along the Texas Coast.  By late May the majority of passage migrants have left the area and continued their northward journey.  Yet this is one of my favorite times to explore the beaches of Galveston Bay, as dozens of species of plovers, sandpipers, gulls, terns, and other Charadriiform birds gather here.  It is during this time that many species are courting and pairing up for the breeding season.

The courtship displays of terns, in particular, are beautiful, elegant things.  I rose before daybreak the day after my workshop, and set out for the the Bay, where I hoped to photograph some courting terns and the array of other species sharing the beach.

Despite my best efforts to avoid condensation, my lens was still hopelessly fogged when I arrived.  I dropped to my knees and worked on resolving this issue when I heard peeping sounds coming from all around me, and caught the blurred movement of small birds scurrying about.  They were Wilson’s Plover (Charadrius wilsonia), beach specialists that breed here. Kneeling appeared to have made my silhouette less threatening, and a number of the birds approached relatively closely.  After several minutes I was able to clear the condensation and dropped to my belly.  While I was in this position, the birds approached even closer, and I was able to capture an intimate portrait of a beautiful male.

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Male Wilson’s Plover

This particular location includes a large bird sanctuary where Wilson’s Plovers and Least Terns nest.  Many of the birds here have been banded and are subjects of long-term studies.  Individual birds may have a combination of colored bands that correspond to sex, age, and other pertinent data, as well as an aluminum band that identifies the individual.

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Banded Wilson’s Plover

I was thrilled for the opportunity to photograph some American Oystercatchers (Haematopus palliatus).  These striking shorebirds have specially adapted bills that help them pry open bivalve shells.  I photographed one as it scoured the Sargassum wrack in search of a meal.

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American Oystercacher

An American Oystercatcher in its prime is a beautiful thing, with clean black, white, and brown lines, bright yellow eyes encircled by orange eye rings, and a long bill that grades from orange to pink to yellow at the tip.

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American Oystercatcher

The dunes adjacent to the Bay were rich in halophytic flora including the lovely Sand Rose Gentian (Sabatia arenicola), which began to open as the morning wore on and the beach warmed.  This species is generally uncommon, and under threat from beach recreation and development.

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Sand Rose Gentian

Before moving onto the main event of courting terns, I took a moment to photograph a Black Skimmer (Rynchops niger).  These wonderfully weird birds have a highly specialized method of foraging that involves flying low and “skimming” the water with their elongated lower jaw.  Once the jaw feels a potential prey item it snaps shut, bringing a meal with it.

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Black Skimmer

Looking down the beach, I could spot a large congregation of Sandwich Terns (Thalasseus sandvicensis) and Royal Terns (Thalasseus maximus).  I knew that many of these birds would be courting, so I devised a plan to approach without spooking them.  I entered the water, which was fortunately relatively calm, and dropped to my belly.  I inched forward for 150 yards or so by slowly dragging myself with my elbows while holding my heavy camera and lens above water.  It was surprisingly physically taxing, and my muscles were screaming by the time I found myself within range.  I rolled over a few times and came to rest in a prime position for capturing the action.  The birds were wary of me at first, but came accustomed to my presence after a half our or so and resumed their normal activities.  Several other birds joined the group, with some landing closer than my minimum focusing distance.

At some point a group of Black Terns (Chlidonias niger) landed within range.  These are spectacular, Gothic looking birds that are just passing through on their journey to breeding grounds in the northern U.S. and Canada.  I was happy to photograph them, despite the difficulties in properly exposing them.

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Black Tern

The Sandwich and Royal Terns were in large groups, so isolating any individual was tricky.  I was happy to capture the Sandwich Tern Below as it stood at the edge of the group, in shallow water that seemed to blend with the distant gray skies.

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Sandwich Tern

The complex courtship displays of Sandwich Terns are fascinating.  They usually begin with aerial displays performed by the males, who will then capture a fish and descend to deliver it to a female.  After the female has accepted, both sexes enter into an elegant, dance-like “strut”.

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Strutting Sandwich Tern

The couple prances down the beach side by side with crests raised.  To initiate mating, the female will move her tail to expose her cloaca, and the male will spread his wings in preparation to mount (see the first image in this blog).  The male then leaps upon her back and after he gains his balance, copulation occurs.

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Courting Sandwich Terns.

After finishing with the Sandwich Terns, I turned my attention to the Royal Terns, which were more numerous.  I captured the image below of an individual that was seemingly left out from the courtship activities.

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Royal Tern

The courting process for Royal Terns is similar to that of the Sandwich Tern.  They begin with aerial displays, followed by the male capturing a fish.

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Royal Tern

One a potential mate has been chosen, the male and female strut in circles around one another.

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Courting Royal Terns

They step in unison…

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Courting Royal Terns

And finally the male presents the fish to the female.

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Courting Royal Terns

One she has accepted, the female moves her tail to expose her cloaca and the male mounts her and the pair copulates.

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Royal Terns preparing to copulate

Sometimes things turn into a bit of a frenzy.  The fish in the image below lost its head when a number of females that were not preferred by the male tried to pilfer the fish from him.  Fortunately he was able to keep the majority of it to present to his intended mate.

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Courting Royal Terns

I find terns to be such elegant animals, and photographing their elaborate courtship allowed me a glimpse inside their complex life history.  And the terns were just the tip of the ice berg that morning!  There are few experiences I cherish more than spending a morning with my belly in the sand, my eye on the viewfinder, and my lens pointed at some feathered thing.  That morning life was good and the beach was beautiful.  Scenes like this, however, are disappearing at an alarming rate, as beach front habitat is rapidly vanishing to commercial and residential development, and the beaches that remain become more crowded with visitors and vehicles.  Coastal habitats, like so many other natural communities, need our help if we want future generations to experience a morning like mine.  Fortunately there are conservation groups actively working to protect this fragile ecosystem.  If these areas and experiences are important to you, please consider donating or volunteering to The Galveston Bay Foundation, Baykeepers, Audubon Texas, and other organizations like them.

Queen of the Summer Night

It’s hard to imagine a more wonder-inspiring  group of animals than the giant silkworm moths of the family Saturniidae.  Anyone lucky enough to encounter one is left awestruck with a memory of the natural world that will last a lifetime.  They are among the largest insects in the U.S., some with wingspans topping six inches, and are decorated with brightly colored, velvety scales of a myriad of colors, from lime green to bright pink.

Among the most impressive of these iconic denizens of the night is Citheronia regalis, known variably as the Regal Moth or Royal Walnut Moth.  This species is, by mass, the largest moth north of Mexico.  They can be found throughout much of the eastern U.S., where they occur in mature forests with a large hardwood component.  They are generally uncommon throughout there range, and appear to be declining in many areas, likely due to a number of factors including habitat loss, pesticide use, and increased urbanization which creates “light traps”, where moths are attracted to artificial lights and perish prior to laying eggs.

I was lucky enough to find the relatively fresh individual pictured below resting below the lights in town.  I brought her to a more remote area where I hoped she might mate, or if she had already mated, find a suitable location to lay her eggs.

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Regal Moth

The life of an adult silkworm moth is both romantic and tragic.  After emerging from their pupae, the clock is ticking to find a mate.  Most species only have vestigial mouth parts, and are unable to feed.  Others do have weakly functioning mouth parts, but still generally do not take food.  Shortly after emerging, females begin filling the air with pheromones, which spread out like chemical tendrils in the night air.  Males may pick up these cues from great distances, and will follow them to the females so that they may mate.  The females then find a suitable host, and lay their eggs.  Within a week of emerging, they are dead.

Regal Moths will utilize a variety of hardwoods, but display a real affinity for hickories (Carya spp.).  The larvae are among the fastest growing organisms on the planet, and will increase in mass by thousands of times from hatching to the point they are ready to pupate.  As they grow, the caterpillars spring barbed spines and take on an appearance so formidable that it has earned them the name “hickory horned devils”.  These spines are purely for show, and they do not sting and contain no toxins.  When threatened, however, the caterpillar may rapidly swing its head from side to side in an attempt to strike a would-be predators.

The caterpillars start off brown and gradually turn green with each molt.  Finally, when they are ready to pupate they take on a bright turquoise hue.  At this point they may be as much as six inches long!  Unfortunately I have never encountered one of this size and color with camera in hand, but I do have an image of one in the brown stage from a few years ago.

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Hickory Horned Devil

Encountering any silkworm moth is a special experience, but spending time with the beautiful Regal Moth is one I will forever cherish.  Like all other organisms great and small, our lives are richer because they exist.