the film forum library tutorial contact

Corps Hopes to Spend $6 Million In FY 2009 to Reduce, Monitor Bird Predation by Staff Columbia Basin Bulletin, January 9, 2009

An aggressive effort is planned during the new (fiscal) year aimed at reaching the goal of reducing the Columbia River estuary's East Sand Island Caspian tern colony by roughly two-thirds by the spring of 2010.

The U.S. Army Corps of Engineers hopes to spend more than $6 million in FY 2009 to develop alternative habitat for the avian predators and monitor the birds. The strategy includes the construction of island habitat for the terns at newly identified sites in northern California's Tule Lake and lower Klamath River regions.

"It's a pretty aggressive program," Corps wildlife biologist Geoff Dorsey said of the construction of five nesting areas this winter and next summer and fall in central Oregon, northern California and the San Francisco Bay.

The avian predation project is highly ranked by the multi-agency System Configuration Team, which prioritizes projects for funding under the Corps' Columbia River Fish Mitigation Program. The program is funded through congressional appropriations which are ultimately reimbursed to the U.S. Treasury by the Bonneville Power Administration.

The president's budget asked for $95.7 million for the CRFMP in FY09 while the Senate has settled on a $92 million figure and the House has weighed in at $88 million. A compromise has yet to be found on the CRFMP, and other, federal budgets.

The idea is to provide suitable habitat for the terns outside of the Columbia estuary, where the world's largest Caspian tern colony builds nests each summer and spring on East Sand. The birds, an estimated 10,700 breeding pairs in 2008, feed on juvenile salmon and steelhead that are headed for the sea, as well as available marine fish species.

The colony was enabled by the creation of East Sand with spoils from the Corps directed dredging of the Columbia's shipping channel. The terns originally began to nest in the estuary in ever-growing numbers upstream at another dredge spoils creation, Rice Island.

But, in an attempt to reduce their consumption of salmon and steelhead, the Corps bared habitat at East Sand to provide open, sandy conditions that the birds prefer and vegetated Rice Island to make it undesirable. The Corps and other involved agencies and tribes theorized that the island closer to the Pacific would provide more marine prey for the terns, and thus divert their attention to some degree from the salmonids.

The shift, completed for the 2000 season, worked. The tern's consumption of salmonids fell from a peak of an estimated peak of about 12 million smolts when the birds nested at Rice Island to less than half that number. The estimated consumption for the past three years has been about 5.5 million smolts annually by the nesting birds.

But the plan is to reduce further the level of predation on salmonid and steelhead in the estuary. Many of the anadromous fish stocks are protected under the Endangered Species Act.

In January 2005 the Corps released a final environmental impact statement on its "Caspian Tern Management to Reduce Predation of Juvenile Salmonids in the Columbia River Estuary Final Environmental Impact Statement." Its "preferred alternative" is to add nesting options in hope of dispersing the East Sand colony, and then reducing available habitat there.

Last year two one-acre sites were made ready for terns, a reconstructed island in south-central Oregon's Crump Lake and a newly constructed island in Fern Ridge Reservoir in Oregon's central Willamette Valley. The strategy allows the East Sand nesting area to be reduced by 1 acre for every two acres of new habitat created.

The original East Sand site included about 6 acres. This past spring the size of the terns' desired habitat was reduced to 5 acres, though the colony only used about 3.6 acres, according to researchers monitoring the island. With the completion of two new sites this winter to provide alternative habitat, the East Sand nesting area will be reduced again.

"This spring we'll drop it to 3.5" acres, Dorsey said.

With other new sites being prepared this fiscal year, "we can get it to 1 acre in 2010," Dorsey said of the management plan's target of ultimately reducing the area of suitable habitat to 1-1.5 acres at East Sand. "At that point birds are going to have to move."

That acreage would hold an estimated 2,500 to 3,125 nesting pairs, according to the EIS. NOAA Fisheries estimated that a reduction in the colony of that magnitude would increase the population growth rate for four listed steelhead stocks by 1 percent or more. Steelhead are a favored target of the terns.

At Crump Lake, terns had been known to nest at the lake intermittently over the years but in small numbers. Researchers this year estimate that about 420 nesting pairs settled in at the rebuilt island. No terns nested at Fern Ridge this year but late season visits by the birds have researchers confident that the island will be inhabited come spring.

"I'm confident that all of the sites we will build will get birds right away," Dorsey said.

Two projects are under way at the Oregon Department of Fish and Wildlife's Summer Lake Wildlife Area in central Oregon about 10 miles southeast of Bend. A half-acre site in the East Link impoundment there is nearly complete and a floating half-acre island will be assembled at nearby Dutchy Lake during January and February, Dorsey said. A third island will be built next summer in the impoundment behind Gold Dike.

Tern decoys and a sound system playing recorded tern colony vocalizations will be installed to attract Caspian terns and researchers will monitor both sites in 2009.

As many as 50 nesting terns have been seen at Summer Lake in recent years, according to the EIS. With the newly created habitat it is estimated the population could rise to as many as 300 pairs.

A project goal is to build two one-acre floating islands in ponds in the Don Edwards National Wildlife Refuge in San Francisco Bay, one in the August-September time frame and one in October-November, Dorsey said.

The project managers would also like to build a two-acre island in the Tule Lake National Wildlife Refuge in northern California in July-August and a one-acre site in the Lower Klamath National Wildlife Refuge northeastern California and southern Oregon in late summer. It is hoped all will be ready when the Caspian terns fly north in the spring of 2010 in search of suitable nesting areas.

The overall project entails the use of social attraction techniques (i.e., decoys and audio playback systems making tern sounds) to draw passing birds to the newly created habitat.

Dorsey said the plan now calls for a second island to be built at Don Edwards and habitat enhanced at Hayward Regional Shoreline, also in San Francisco, next fall. A second island, this one floating, could also be build at the Lower Klamath NWR early in FY 2011.

Habitat enhancements are targeted in 2011 at the Bay Area's Brooks Island. Brooks and Hayward are both managed by the East Bay Regional Parks District.

The CRFMP "avian predation" project also includes continued monitoring of Caspian tern activities at East Sand and at the newly created sites in 2009. Researchers are also assessing the impact of salmon from double-crested cormorants. East Sand Island is also host to the world's largest cormorant colony. The preliminary FY 2009 cost estimate for the project is $6.7 million. Corps officials stress that the cost estimates are continually being fine-tuned and subject to change if facets of the project are changed or eliminated.

A second avian predation project in the running for CRFMP funding would focus, principally, on the tern colony on the Mid-Columbia's Crescent Island and a cormorant colony on the Mid-Columbia. Its preliminary 2009 budget is $1.9 million.

"We're planning to continue the research we've done in the past," said Corps research biologist Scott Dunmire. The evaluation of Crescent Island tern impacts on listed salmon and steelhead wraps up this year while the cormorant study would continue beyond 2009. The goal of both is to determine if some sort of management action is warranted to reduce avian predation impacts.

A NOAA Fisheries Service biological opinion for the Federal Columbia River Power system calls for the development of an inland predation management plan. The ESA BiOp requires that dam operations don't jeopardize the survival of listed species. As federal "action" agencies that operate the dams, the Corps and Bureau of Reclamation have ESA obligations. BPA, which markets power generated in the hydro system, provides funding for fish and wildlife mitigation as a result of ESA, Northwest Power Act and other obligations.