Illustration: Jonathan Bartlett
In 1979 another in a growing line of alien species hitched a ride on a fishing skiff from a remote village on Mexico's Baja California peninsula to land on Rasa Island, a tiny sun-blasted wafer of rock in the Gulf of California. The invader was Enriqueta Velarde, a petite 25-year-old Mexican graduate biology student who looked 18, with a comely smile and an adventuring heart. It was the launch of her Ph.D. research into one of the island's resident species, the Heermann's gull, a petite, pretty bird about which almost nothing was known. In fact, little was known of the island beyond its desolate oddities: thousands of mysterious stone cairns and pathways thought to have been made by guano miners in the 19th century, three wooden crosses marking unremembered graves, a stone hut crumbling with the region's frequent temblors.
Velarde arrived at the beginning of the three-month cacophony known as the breeding season, when Rasa's 148 desert acres become a fecund madhouse of hundreds of thousands of noisy, copulating seabirds who have for at least millennia chosen this smidgen of refuge because it's flat in a world of mountains and because it was once free of terrestrial predators that threatened their eggs and chicks. The birds arrive from coasts to the north and south, homing so faithfully to Rasa each year that at some time in the distant past they diverged from their progenitors to become their own kind: species we now call elegant terns and Heermann's gulls, virtually all of whom nest only here.
The island had been of interest to ornithologists as early as the 19th century, but though some intrepid adventurers had visited, none had stayed. Velarde's landmark arrival would prove a rarity in both the human story and the biological story: a successful invasion by one who would not go on to populate the island with her own kind, yet whose presence would transform Rasa and its larger ecosystem forever.
As an undergrad biology major, I joined Velarde for her second field season on Rasa in 1980. Last year, I returned. Some things haven't changed. Velarde still moves across the island in the slow-motion style I remember, treading between one gull nest and another, foot poised in the air as she examines where to plant it to avoid stepping on eggs and chicks that perfectly mimic the ground splattered with guano in all its wet and dry incarnations. But Heermann's gulls nest on virtually every square inch of Rasa, and even our careful footfalls violate the territorial integrity of one bird after another so that we trigger a cascade of incensed nesters who burst into the air and scream past our heads, firing globby rains of shit upon us. A few slap us with webbed feet or smack us with bills. Velarde gently redirects them with a clipboard cocked over her head.
We're headed to the tern colony in one of the largest of the island's 11 small valleys. This is where I spent most of my time in 1980, perched on uncomfortable rocks, baking in the sun, observing through binoculars the nearly incomprehensible machinations of delicate white birds—the rare elegant terns nesting alongside nearly identical, but more common, royal terns—all jammed only a bill's length from their constantly jabbing neighbors. Compared with the dull roar of a gull colony, the tern colony sounds like a jet-fueled apocalypse slipping off a million broken flywheels, so shrill and piercing it's a physical assault. Long before we can see these birds, we can hear them.
The tern colony at Rasa Island in 2011. : Julia WhittyBut when we try to climb the old path to the tern valley we routinely walked in 1980, we're stopped by thousands of terns nesting on the ridge, a rocky place they never utilized back then. We choose not to trespass through their colony, since nesting terns are hypersensitive to disturbance, and in fleeing us they could lose their eggs to marauding gulls. So we backtrack and try to cross in a different place, only to be stymied by more nesting terns. When we finally find a route, we come face-to-face with a sight I could never have imagined in 1980: Where once there was a small amoeba of a colony of terns, today there are multiple gargantuan superorganisms of colonies usurping nearly the entire valley.
Velarde is part of a widely dispersed bunch of misfits, frequently women, who guard their wilderness nests with near-mythical ferocity.
"Does it look like a lot more terns than you remember?" Velarde shouts above the mayhem.
She estimates there are some 200,000 now. Seven times the 1980 number.
A multitude of factors have allowed these birds to buck the trend of dismally declining wildlife. Each traces its genesis to this small, now gray-haired woman before me.
It took me years to see that Enriqueta Velarde was part of a widely and thinly dispersed bunch of like-minded misfits, frequently women, who travel to earth's last hinterlands and guard their wilderness nests with near-mythical ferocity. I met the matriarch of this clan, Jane Goodall, on the 25th anniversary of her work with wild chimpanzees at Gombe Stream in 1985. She didn't actually expect our small film crew to persevere all the way to Gombe, I could tell, to weather the challenges she routinely encountered en route to the chimps' world. And suffer we did: Arrested in Dar es Salaam, shipwrecked on Lake Tanganyika, rescued by Zairean (now Congolese) war refugees, we hungered and thirsted and lived for a while on bottles of konyagi and nothing else. When we finally made it to Gombe, long after our scheduled arrival, beaten down by our cinematic adventures, Goodall greeted our knock at her door in the wilderness in utter darkness with serene and unruffled composure and listened bemusedly as we breathlessly unloaded our stories. She'd already heard, or lived, some version of all our escapades.
From Goodall I learned the power of one. Alone, she had managed to preserve Gombe's postage stamp of verdancy amid a combat zone of stripped forests and eroding hillsides unable to support either people or chimpanzees. In ecology-speak, a keystone species is one with a disproportionate effect on its environment relative to its biomass. In Goodall, I realized, I'd met a keystone individual.
Over time I met other keystone humans stubbornly attached to remote rainforests, wetlands, mountains, deserts, and coral reefs, influencing these areas far beyond their mortal size. A few had attracted enough National Geographic coverage to become household names, though most accepted obscurity as a prerequisite of isolation. Yet their unknown stories of quest, conflict, discovery, and understanding are important to us—resuscitative sagas in a demoralizing age.
And that's a kind of keystone idea that science itself is grappling with in the face of obstinately gloomy news about the natural world. The authors of a clarion paper in Trends in Ecology and Evolution last year defined the challenge: "Relentless communication of an impending mass extinction is, self-evidently, having insufficient impact on politicians, policy makers and the public, and could eventually even be counterproductive for improved conservation," wrote Stephen Garnett and David Lindenmayer. "Researchers need to provide the science not only for the campaigns lamenting environmental loss, but also, most importantly, for those celebrating the effectiveness of conservation."
That effectiveness is consistently underrated. It has been only 164 years—an eyeblink in the human life span—since George Perkins Marsh, a congressman from Vermont, bore witness to the loss of Eastern forests and suggested we ought to conserve them. (His writings helped launch the modern conservation movement as well as the Adirondack Park, today the largest publicly protected landscape in the contiguous United States.) Marsh's heretical notion came on the heels of near-total deforestation in the East and only months before unbridled gold fever would level California's wildlands. Yet since then we have with radical speed rearranged our relationship to 160,365 landscapes to preserve 14 percent of terrestrial earth and created 6,967 marine protected areas sheltering 1 percent of the planet's ocean. We've enacted sweeping legislation to conserve flora and fauna in most nations and even across tricky international borders. We've widely abandoned the notion of infinite resources and begun to redirect our human story toward the idea of sustainability.
While the dominant meme sees only our destruction of nature, a keystone idea might be that we're actually in the middle of a new process whereby nature is tweaking the design specs on its most ingenious piece yet of evolutionary engineering: human understanding.