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On East Sand Island at the Mouth of the Columbia River, Cormorants and Terns Feast on Endangered Salmon by Quinton Smith The Oregonian, June 14, 2011

EAST SAND ISLAND -- From a tower on this spot in the lower Columbia River, Adam Peck-Richardson and Brad Cramer peer at double-crested cormorants almost as far as their binoculars can see. The migrating ocean birds are building nests.

They settle in specially placed tires or rock riprap, in a few scraggly bushes, on the sand and along a 200-foot-long plastic tunnel leading to the tower -- anywhere that supports sticks. The noise is constant; the smell nearly overwhelming.

The biologists are counting birds, eggs and eventually chicks. Wielding antenna and receiver, they also record electronically tagged cormorants moving from one side of an experimental 10-foot-high fence to the other. Thirteen researchers will spend four months on this island five miles from the Pacific Ocean. They are the front edge to try to fix a man-made mess by moving some cormorants to nests as far away as British Columbia.

Already there have been surprises. On the other side of the island where Caspian terns breed, nature may be re-balancing itself. In the past two weeks, bald eagles and gulls wiped out all 5,000 of this year's nests. It reinforced biologists' goal to disperse the terns to protect the West Coast population and provided a harsher but sooner-than-expected opportunity to see the effects of pushing the birds out.

Terns and cormorants are voracious consumers of fish, among them endangered juvenile salmon and steelhead. Shrinking the massive island colonies is part of a complex effort to protect those fish and a larger strategy to keep dams operating on the Columbia and Snake rivers.

The Bonneville Power Administration estimates it spent $800 million in 2010 for fish: habitat, hatchery and hydro programs, or lost power purchases when dam operations are restricted -- all to give salmon and steelhead a better shot at reaching the ocean.

Up to 120 million smolts pass by this island each spring. Some 25 million don't make it past the world's largest nesting colonies of cormorants and Caspian terns, which makes them by far the largest source of salmon and steelhead predation in the Columbia system.

"The birds have become a significant mortality factor on endangered salmon and steelhead," says Dan Roby, a U.S. Geological Survey scientist at Oregon State University who leads research on cormorants and terns in Oregon, Washington and California.

It is a conundrum that only man could make -- and is now trying to solve.

In the beginning

The U.S. Army Corps of Engineers dredged the Columbia River channel in the early 1980s and used the material to greatly expand Rice Island, 21 miles from the ocean. Terns found it ideal for nesting -- flat, bare sand, free of predators -- as their habitat elsewhere shrunk from development. By 1998 the island was home to 16,000 terns who plucked out 12.4 million fish or about 13 percent of the run.

Under the Migratory Bird Treaty Act, terns cannot be physically harmed. But over the next three years the corps shrunk Rice Island's nesting area and used hazing and decoys to move all the birds to East Sand Island, another creation of the corps' dredge spoils. Its six acres of bare sand also offered a wider variety of fish from the estuary. Once moved, smolt consumption dropped by 4 million.

"It was amazing how quickly they moved," says Roby. "The idea was to keep them moving to places like Willapa Bay, Grays Harbor and Everett, Wash."

Instead, they stopped -- and kept growing. Alarmed, the National Marine Fisheries Service required the corps and the U.S. Fish and Wildlife Service to scatter the terns. In 2006 the agencies announced plans to slowly cut East Sand Island's tern habitat to two acres and build nesting sites in the Klamath Basin, Lane County and the San Francisco Bay Area. Dispersing the big colony would also lessen the impact if a catastrophic event -- predation by other birds or bad storms during nesting.

Last year 16,000 terns nesting on 3.1 acres ate an estimated 5.3 million smolts. This spring the nesting area dropped to two acres and 10,000-12,000 birds. The goal is 7,000 terns by 2015, Roby says, to cut smolt consumption another 3 million.

The cormorants enter

A mile west of the terns, the double-crested cormorants make themselves at home. Last year there were 27,000 cormorants, nearly triple the number in 1997. This year more than 1,300 Brandt's cormorants and 3,300 California brown pelicans joined them.

After a decade concentrating on terns, agencies were startled when Roby reported the cormorants ate 19 million migrating salmon and steelhead last spring, almost four times that of the terns.

"Suddenly the focus shifted to cormorants," Roby says. A working group of biologists from tribes, state and federal agencies formed in November to come up with a plan to start moving cormorants by 2013.

But cormorants adapt better than terns, so simply reducing habitat on East Sand Island will not shoo them off elsewhere.

"What will it take to move them off this island and not to just another place on the island?" says Jenny Hoskins, a U.S. Fish & Wildlife Service biologist leading the effort.

Cormorants have mostly abandoned coastal nesting areas along British Columbia and Washington in favor of East Sand Island. Oregon and Washington have a big stake in salmon survival, but Oregon already hazes cormorants in Nestucca, Tillamook and Nehalem bays to keep them off ocean-bound smolts.

That's what Peck-Richardson and the other observers are trying to figure out. Their research tests if the big fence and other barriers over part of the cormorant nesting area pushes the birds off the island or simply farther west

"Can we guarantee where they are going to go?" Roby says. "Probably not."

Nature steps in

But what man can't fix, sometimes nature tries.

While the two big colonies have always attracted eagles, owls and gulls, the number of bald eagles and their effect this year is "unprecedented," says Peck-Richardson.

This month more than a dozen bald eagles destroyed 15 percent of the double-crested cormorant nests and 80 percent of the Brandt's cormorant nests. It was worse for the terns. A bald eagle, falcon and owl continually flushed birds off their nests allowing gulls to swoop in to eat their eggs.

"We went from 5,000-6,000 nests to zero nests in two weeks," Peck-Richardson says. Although 10,000 terns remain on the island eating fish and trying to nest, he says, their eggs don't last more than a few hours. It would take two or three consecutive years of failed nesting to affect the population.

"Unless something changes, I think it's going to be a total failure of the colony this year," says Peck-Richardson.

It might explain why some of the birds have been spotted in the Klamath Basin, a few others along the Washington coast, Puget Sound, and even as far away as Alaska.

"It's been unbalanced and maybe it's nature trying to re-balance itself," says Peck-Richardson.

Oregon Field Guide reports on eagle attacks on murres:

Oregon Field Guide reports on terns & cormorants in 2008:

Related Sites:
Video of Eagle stealing fish from Caspian Tern

Related Pages:
Survival of Snake River Salmon & Steelhead Data compiled 2004 by bluefish.org
Steelhead-Munching Mid-Columbia Terns Fingered in Report by Bill Rudolph, NW Fishletter, 5/12/11
Bald Eagles Decimate Tern and Cormorant Colonies by Vince Patton, The Oregonian, 6/13/11
Bald Eagles' Predation Decimates Salmon-Eating Tern Colony by Staff, Columbia Basin Bulletin, 6/10/11