Borderland
Birds Overheard: Issue 4
Every so often, a chance encounter will remind me how little I know about my home. One cloudy afternoon last July, my new friend Arnau led me over the deserted sands of Imperial Beach in search of nesting California least terns. In the year since his arrival from Barcelona, Arnau had wasted no time getting to know our local population of these endangered birds. When he discovered that I had never seen one, despite having lived in San Diego most of my life, he immediately volunteered to be my guide. We arrived at half past five, cameras in hand. Although we had come to photograph newly-hatched chicks, the most vivid image I carried home from our excursion was a mental picture of the landscape’s contradictions.
Located in the southwesternmost corner of San Diego County, the Tijuana River Estuary isn’t just a borderland between the US and Mexico—it also separates land from sea, saltwater from fresh. While the river empties on the US side of the border, it primarily flows through Mexico, picking up sewage and industrial waste, then meanders through 2,300 acres of wetlands before it meets the Pacific Ocean. This estuary, the largest in Southern California, is so polluted that local officials want to make it a Superfund site, but it still supports 370 species of birds, a key rest spot on the migratory route known as the Pacific Flyway.
It’s also one of the easiest places to spot California least terns, who share their human neighbors’ taste for beachfront real estate, nesting in simple scrapes among the dunes. Over generations, they’ve evolved to match their eggs to their surroundings—pale blonde, speckled gray, sometimes reddish—camouflage that protects them from predators but leaves them vulnerable to trampling. Thankfully, a cord fence stretched along the dune, a discreet reminder to keep a respectful distance. As we walked along it, we noticed that some terns seemed indifferent to these human-made boundaries, nesting just inches from the posts.
Other boundaries were visible in the distance. To the south, the border fence stabbed into the water like a rusty nail, hotels and houses pressed close on the other side. Overhead, three Seahawk helicopters circled the estuary, lifting off from an airstrip visible to the east. A training mission? A show of force? By comparison, the terns were models of grace: natural selection had honed every angle of their nine-inch bodies to a razor’s edge. They hovered, dodged, and strafed with an agility that put their human counterparts to shame, and when they spotted prey, they skimmed along the ocean’s surface, beak open, slicing through the water with surgical precision. Although the terns seemed willing to share the skies, the contrast felt jarring: the roar of rotors drowned out their gentle killick, while jet fuel and steel loomed heavily against feather and bone.
Curious about the juxtaposition, I later read that the US military has used this land since 1929, first as a machine gun range, then as an air station. While explicitly violent, these uses spared the estuary from the civilian coastal development that eventually destroyed ninety percent of Southern California’s wetland habitat. Although a developer called Helix Land Corporation did begin purchasing land in the 1970s in a decade-long effort to turn the estuary into a marina, by that time the growing environmental movement had gained enough traction to mount a successful resistance, and the US Fish and Wildlife service eventually bought the land, establishing today’s refuge. The pattern repeats further north: Miramar and Pendleton are still active bases, but they have also become islands of habitat in a landscape dominated by suburbs.
Taking in the scene with my Catalonian friend, I couldn’t help but feel a little sheepish. San Diego holds both the greatest biological diversity and highest concentration of military personnel of any county in the contiguous United States. Although the biological diversity arrived first, it seems that within the past century, the military has played an undeniable role in keeping it around. How’s that for an unexpected tern?
Birds Overheard is a column and linocut series published in Mail Mag, a monthly zine by Burn All Books.
