The Rise and Fall of the East Sand Empire
On the Columbia River, Conservation Biologists Find that Whatever Can Go Wrong, Will
East Sand Island sits near the mouth of the Columbia River. Although the mound of sand and dredge spoils is only a mile or so long and a few hundred yards at its widest, it hosts one of the largest seabird colonies in the United States. Stand on the north beach: To your right, on the western tip, are tens of thousands of cormorants; to your left, on the eastern tip, several thousand Caspian terns. Thousands of gulls are between them. Thousands more brown pelicans transit stiffly hither and yon.
For the terns, the colony is their largest in North America, and perhaps the world. This is not a good thing. “We didn’t set out to have the world’s largest tern colony,” says Dan Roby. “We would have been happy with the fifth- or sixth-largest. But that wasn’t how it worked out.”
Roby is a biologist at Oregon State University. For almost 15 years he has studied the terns as part of an ambitious and delicate effort to accommodate the needs of several federally protected species. Some of those species – the various runs of salmon and steelhead – are valuable commodities, both culturally and financially. The other – the tern – is not. It is a fine balance, and one that can make Roby wry. “Ecology very often has different ideas than we do as managers,” he says. “That isn’t a new realization. But perhaps it’s good to be reminded of that from time to time.” At East Sand Island, he tells me, he is reminded of it quite a bit.
When they were willing to put such things in print, biologists called the Caspian tern “the king of all terns.” With a white body, light gray back, black cap, and bright coral red bill, they are a common sight on the lower reaches of the Columbia, patrolling on long thin wings, heads down, scanning for fish. When they see one, they plunge into the water arrow-straight, rising with a flash of struggling silver in their bill.
On a warm and windy summer afternoon, the colony is bustling, a near wall of sound. From my vantage in a large blind, I can the see it in its entirety, covering a little less than two acres of bare sand. A look around reveals just how intensely these terns are observed. A few yards from this blind is another one; the sun flashes off binocular lenses poking out a window. The ground is stitched with a grid of colored ropes and small stakes. A tall fence of black plastic mesh encircles the whole space, intended to restrict the terns to this patch of land and no more.
In the blind with me is Adam Peck-Richardson, a seasonal field worker of Roby’s who has spent the last few summers at the colony; Michelle McDowell, a biologist with the US Fish and Wildlife Service; and an official whose name I didn’t catch from the US Army Corps of Engineers, which owns the island. “There, that one,” says Peck-Richardson, pointing to a flying tern. “That one is holding a salmon.” The company takes note, murmurs. This is not a good thing, either.
On the Columbia River, Conservation Biologists Find that Whatever Can Go Wrong, Will
To understand the contretemps of East Sand Island – why the birds are so confined, why many that are here now probably won’t be for much longer, and why that might be a desirable – it is necessary to go to Rice Island, a similar mound of sand and dredge spoils 15 miles up the Columbia. There, in 1986, roughly 1,000 pairs of terns decided to nest. They did well, and in the following years more came. They were drawn, Roby says, by food and driven by the loss of habitat elsewhere.
Before long, there were nearly 10,000 pairs, and the colony started to attract the notice of various government entities concerned with the terns’ diet. At Rice Island, the terns subsisted largely on salmon and steelhead smolts (juvenile fish), which, as they migrated to sea, were funneled through a narrow chute of river. Thirteen of the 20 salmon and steelhead runs in the Columbia River basin are listed under the Endangered Species Act. Federal, state, and tribal agencies (which were spending hundreds of million of dollars each year to bolster declining fish stocks) winced as 11 to 12 million smolts – more than 10 percent of all that pass through the estuary – disappeared down tern gullets.
In 1998, a consortium of government agencies decided that the terns should be moved from Rice Island to a place where they would eat fewer salmon. Biologists settled on East Sand Island, and so began one of the largest attempts to relocate a seabird colony in recent memory.
First, the Army Corps of Engineers, which also owns Rice Island, set about making it unattractive to the birds. They covered the terns’ beaches with mesh, set streamers to flap in the wind, and planted winter wheat. At the same time, they made East Sand Island more alluring. An engineering unit of US Marines was sent to bulldoze a space for the terns. Tern dummies were set up, tern calls loudly piped over speakers.
“People laughed at us when we first proposed this,” Roby says now. “But terns are good at finding opportunities to nest. Some birds are always keeping an eye out for new potential colonies.” They were quick to find East Sand Island. The first pairs bred there in 1999. By 2001, the Rice Island colony was no more, moved in full to East Sand Island, where it thrived. As hoped, the birds ate fewer salmonids; rather than comprise 75 percent of their diet, smolts made up about 30 percent. Today, even as they catch 4 to 5 million smolts per year, they survive mostly on marine fishes: anchovy, herring, sardine.
But ecology has a way of being complicated and unpredictable, and two recent events threaten to undo those years of careful planning. The first is the increase in double-crested cormorants on the western edge of the island. Their rise has mirrored that of the terns: Since 1997, the number of cormorants has increased from a few hundred to well over 25,000. Until now, though, they were thought incidental; biologists’ management always focused on the terns. Not as much was known of the cormorants or, more to the point, their eating habits, which are generally more flexible than terns. Then, last year, Roby found that the cormorants ate close to 20 million smolts. “It was the first year that their salmonid consumption exceeded the terns,” he says. Together, they were eating about 20 percent of all the salmon heading to sea. “It set off a lot of alarm bells.”
The tern colony itself has suffered a series of setbacks. In 2010, productivity plummeted. Last year, not a single chick survived. Roby blames extenuating circumstances. “A lot of things happened at once,” he says, “and it was just too much for the terns.” There was distant, trickle-down misfortune. When an unusually deep snowpack in the Cascade Range melted, the federal agency responsible for the Columbia River dams was obliged to spill tremendous amounts of freshwater over them. The estuary was thus a lot fresher than it would normally be. The marine fish that terns depend on were pushed farther out to sea, and so were harder to find.
Other troubles were more immediate. The colony, after years of relative peace, started to attract bald eagles, peregrine falcons, and great horned owls, all of which eat smaller birds like – that’s right – terns. None of those predators do more than snatch the occasional adult, but their presence has indirect effects. “There was one juvenile eagle that would just come and hang around the colony,” Peck-Richardson says. “The terns would all be in the air, going nuts.” When the terns left their nests, gulls would steal in. They ate almost every unattended egg.
Watching the terns now from the blind, I ask Peck-Richardson how this season is going. He tells me that things are looking pretty good. There seem to be a fair number of chicks, and most look fluffy and fat. The eagle that caused so much trouble hasn’t returned, and there seem to be more fish. “Terns can take a bad year or two,” he says, “but more than that and they might give up on the place.”
A few minutes after he says this, a bald eagle flies past the colony, and all the terns take to the air. They wheel around, shrieking. The motion and noise are so mesmerizing that I barely hear Peck-Richardson when he says, “Look.” Beneath the wailing terns, a gull has landed at the edge of the colony. When it sees no adult terns rushing to confront it, it grabs a nearby chick. It thrashes the chick dead and starts to swallow it. The chick’s legs stick out stiffly as the gull chokes it down.
“I think we’re going to see more and more of these situations,” Roby tells me later, as we plod between the colonies. “There’s so much human development along the Pacific Coast that we risk losing our native species if we don’t let them use what habitat they can.” Still, the East Sand Island colony will continue to be cinched tighter, the black mesh walls brought a little closer each year until the number of terns is deemed acceptable. “We want to get it so we have thirty-five hundred pairs or so,” Roby says. “We’d still be one of the top ten colonies size-wise.”
To offset habitat losses, the Army Corps of Engineers is building small islands throughout southeastern Oregon and parts of California. Displaced terns will have at least another nine acres at their disposal, with more potentially on the way. The ratio of replacement is precise: two new acres for every acre lost on East Sand Island.
Roby is confident that the terns will make use of these new spots. Terns’ fidelity to their nesting site is not like that of other seabirds, some of which return to their natal colonies for their entire lives. This flexibility is due to a behavioral quirk. Since they nest almost exclusively on bare sand islands, and these can be quite ephemeral, terns are quick to find new habitat and colonize it. “It’s a real fugitive lifestyle,” Roby says.
The cormorants, meanwhile, will have to fend for themselves. Across the country, they have not fared too well when their tastes overlap with people’s. Down the Oregon coast, in Tillamook, they are hazed to keep them from eating salmon and steelhead smolts; at catfish farms throughout the southeast US, they have simply been shot. Both options are being considered here, although Diana Fredlund of the Army Corps assures us that no final decision has been made.
In an effort to avoid lethal controls, Roby and his crew are trying to drive the cormorants away, also by shrinking their colony. In what they call the Dissuasion Zone, field crews put up a series of fences between which cormorants were excluded. “Every morning,” says Brad Cramer, another of Roby’s field workers, “we’d walk out and take apart their nests.” But cormorants are persistent, and it would be a while before they figured out they weren’t wanted. “Early on, we had to go out five or ten times per day,” Cramer says. “Now, we only go out once a day or so.” Much to everyone’s consternation, though, the cormorants didn’t leave so much as compress, as thousands of birds packed into successively tighter spaces. Like the terns, the colony is now bracketed by walls and tunnels and large blinds. It looks like a prison camp.
“The first rule of intelligent tinkering,” Aldo Leopold wrote, “is to save all the pieces.” Today, though, the question is no longer one of just saving all the pieces, but also trying to relocate entire ecologies to places where they are more convenient for people. If a colony of terns is eating too many salmon, move them. If they continue to eat too many salmon, scatter them around the West. Such is the nature of adaptive management. McDowell, the US Fish and Wildlife biologist, argues that this is an oversimplification. She talks about balancing the needs of protected birds and fish. She says something about “making progress” and “looking for the win-win.” Still, we obviously wouldn’t be sitting in a blind watching soon-to-be-twice-moved terns if salmon weren’t involved.
Even the whole debate is, in a way, a distraction from the main threats to salmon: dams, overfishing, habitat loss, competition with hatchery fish. The terns are merely an aggravation to bigger problems – problems that we aren’t willing to address with the same singular focus. It’s not that the birds are scapegoats, exactly, or that the number of smolts they eat is trivial. It’s just much easier to shuttle around a few thousand seabirds already disposed to nomadism than to dismantle the physical and political infrastructure of hydropower in the Pacific Northwest.
We all leave the blind and start back to the boat that will take us to the mainland. As we tramp across the sand, we can hear the rasps and screeches of thousands of terns. Adults spirit over on their way to forage on the river. Some, when they see us, streak away even faster. But others turn back toward us. They dive on us, wings pumping, sweeping over our heads and crying out, telling us to leave them alone and mind our own business. As if we could.
Eric Wagner is a Seattle-based freelance writer. His last article for the Journal was about crane conservation in China.