Are birds to blame for vanishing salmon?

  • VORACIOUS: Terns on Rice Island

    Daniel Roby photo
 

ASTORIA, Ore. - In late May, when young salmon and steelhead ride the spring freshet down to the mouth of the Columbia River, Rice Island is a scene of wildlife bedlam. The island, a stretch of windswept sand 21 miles from the river mouth, hosts the world's largest nesting colony of Caspian terns - as many as 20,000 of the big, elegant seabirds lived on the island during the summer of 1998.

Screaming terns battle for nesting space and fight off gulls that eat most of their chicks. "It's wonderful but chaotic," says Daniel Roby, a wildlife biologist with the Oregon Cooperative Fish and Wildlife Research Unit in Corvallis. "And it's a sobering place to be, because there is so much life, but there is also so much death taking place at the same time."

The death is not limited to birds. Roby and his fellow researchers are finding that the terns take a heavy toll on the Columbia's endangered salmon and steelhead. "The evidence we have for the terns is that they're taking between 5 and 25 percent of all the smolts (young fish) that make it to the estuary," says Roby. "That's a lot, particularly when the Bonneville Power Administration and the (Army) Corps are spending millions of dollars a year to improve fish passage around the dams by just 1 or 2 percent."

Now, the state and federal agencies that manage salmon in the Columbia want to save fish by driving the terns off Rice Island. The plan has birders and environmentalists crying foul.

Don't blame the birds

Blaming the terns for declining salmon runs "is tantamount to coming home after an unsuccessful day at work and kicking the family dog," says Craig Harrison, a former U.S. Fish and Wildlife Service biologist and current vice chairman of conservation for the Pacific Seabird Group, a nationwide coalition of seabird biologists and managers. The real problem is people, not birds, he says. Dams, ranching, logging, and other human impacts have led to massive degradation and loss of salmon habitat.

Harrison also points out that the terns, like cormorants and other fish-eating birds, are protected by the Migratory Bird Treaty Act, which prohibits killing nongame migratory birds or disrupting their nests. He is alarmed by some of the possible management options in a plan recently released by the Oregon Department of Fish and Wildlife, which include harassing terns and cormorants, introducing predators such as mink and fox to the nesting islands, and even shooting seabirds.

He and other seabird biologists point out that Roby's study results are still preliminary - this year was the second year of a planned five-year study of seabird predation in the estuary.

No time to waste

But the U.S. Fish and Wildlife Service and its interagency Caspian Tern Working Group say waiting for more data is not an option. Officials point out that Rice Island didn't even exist until the Army Corps of Engineers started dredging the Columbia and dumping the dredge spoils near the river mouth.

Every live salmon smolt that reaches the estuary is the result of years of work and billions of dollars spent to correct impacts from hydropower dams on the Columbia, says Herb Pollard, a fisheries biologist with the National Marine Fisheries Service. He estimates that seabirds swallow $60 million worth of salmon smolts each spring. "How do you face some cowboy up in the Stanley Basin and tell him he's got to get his cows out of the creek to produce another 300 or 400 smolts," he asks, "when we know that 20 million of them are dying because of something that we did down here?"

This winter, wildlife managers will begin to make Rice Island less attractive to terns by planting shrubs on the island and putting netting over nesting areas. When the terns begin to arrive next spring, managers will chase them off the island. The hope is that the birds will nest instead on East Sand Island, closer to the river mouth, where they may find fewer salmonids and more marine fish like sand lance and herring.

"It's the only win/win solution we can see to this problem," says Roby.

Craig Harrison says the terns will lose. "The notion that a colony of birds can be moved like moving a building is a notion that comes from engineering, not biology," he says. He has written letters to the agencies involved, but so have 10 members of Congress - all of whom support the plan to move the terns. He is not hopeful that seabird advocates will be able to stop it.

You can contact ...

* Chris Wheaton with the Oregon Department of Fish and Wildlife at 503/872-5260;

* The Oregon Cooperative Fish and Wildlife Unit, 541/737-1938;

* Craig Harrison with the Pacific Seabird Group at charrison@hunton.com.