ADEL, Ore. — An island built by the U.S. Army Corps of Engineers in southeast Oregon has become a surprisingly popular new home for birds that had been eating protected salmon in the Columbia River.
More than 50 nesting pairs of Caspian terns were counted this spring on an island in Crump Lake, near the tiny community of Adel at the southeast corner of the Hart Mountain National Antelope Refuge.
Some of the birds wear colored bands on their legs that show biologists they have moved from islands in the Columbia estuary near Astoria and another island near the Tri-Cities in Washington, said Dan Roby, an Oregon State University professor who is a lead scientist on the project to move the terns from the Columbia.
An OSU-led team calculated that the tern colony ate some 12 million young salmon and steelhead in one year when it nested on a different island farther up the Columbia.
In the late 1990s, the U.S. Army Corps of Engineers moved the terns to East Sand Island, which is closer to the ocean and offers the birds a wider variety of fish. But the terns still munched millions of salmon migrating toward the sea.
That led to the Corps to sponsor an effort to move the birds much farther away.
The new nesting sites include the new island at Crump Lake, a similar island built in Fern Ridge Reservoir in the Willamette Valley, islands to be built in Summer Lake and construction of new sites in the San Francisco Bay area.
The work is being funded by the Army Corps of Engineers and Bonneville Power Administration, which are responsible for helping protect salmon affected by hydroelectric dams on the Columbia.
Researchers helped lure terns to the new island with decoys and sounds of nesting terns recorded in the Columbia estuary. While the birds that have moved to Crump Lake still represent only a small fraction of those in the estuary, their rapid arrival suggests it is possible to lead the birds to new nesting sites.
“The almost incredible part of this is how fast word gets around among these birds,” Roby said.
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