Tag Archives: interior least tern (Sterna antillarum athalassos)

Even if it had been by candlelight

The interior least tern (Sterna antillarum athalassos) is an endangered species.  Changes to riparian habitats where the birds nest, pollution affecting fish populations, human activity around breeding and nesting sites, the building of reservoirs and the diversion of waterways, and accumulating chemicals from runoff resulted in a catastrophic decline of these terns throughout North America.  Thankfully, Dallas hosts one of the few remaining sites in Texas where the birds breed and rear their young before returning to the coast for winter.  And it just so happens that White Rock Lake is one of their favorite haunts.

Interior least terns (Sterna antillarum athalassos) sharing a fish in courtship (2009_07_31_028175)

Though the birds remained far out at the edge of the water theater behind the Bath House Cultural Center, and though the sun had already set and dusk was quickly giving way to nightfall, I stood back some distance from the shore[1] and watched a pair of these terns.

Interior least terns (Sterna antillarum athalassos) flying from their perch (2009_07_31_028174)

Much to my delight, they gifted me with a view of the very sweet courtship ritual called “fish flight”[2]: “an aerial display involving aerobatics and pursuit, ending in a fish transfer on the ground between two displaying birds.”  The female would find a perch on one of the many theater platforms and call out to the male; meanwhile, he flew back and forth, eventually diving into the shallows.  Each time he succeeded in capturing food, he’d return to his mate and proffer it gently.[3]

Interior least terns (Sterna antillarum athalassos) sharing a fish in courtship (2009_07_31_028184)

When she accepted the gift, he would celebrate with wings held out and head held high.  So late in the season, this part of their courtship is intended to strengthen their existing bond as opposed to wooing a new mate.

Interior least terns (Sterna antillarum athalassos) sharing a fish in courtship (2009_07_31_028194)

They repeated this time and again[4], and each time he would flit into the air afterward to hunt some more while she would soar to a different perch to dine on the delivered meal.

Interior least terns (Sterna antillarum athalassos) sharing a fish in courtship (2009_07_31_028195)

It could not have been a more delightful and romantic display.

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[1] This species is notoriously sensitive to human activity and presence, so much so that simply by being near them we interfere with their ability to court, mate, nest, and brood and raise young.  Rather than stand at the edge of the water where I would be much closer with a better view, I chose to keep my distance out of respect for them and their absolute need to be away from us.  Hence the poor quality of the photos, especially since it was after dark.

[2] Via Texas Parks and Wildlife Department.

[3] I admit at the time I took these photos that I assumed I was watching a parent feeding a child.  Distance and lack of light conspired against me having a clear view of them.  It wasn’t until I got home and processed the images that I saw both were in breeding plumage—which completely negated the possibility of either of them being young enough for parent feeding.

[4] Each of the photos shows a different fish gifted to the female by the male, hence he caught at least five while I watched.  Then it became too dark to see them.