News Release
| Release Number: | 00-041 |
| Dated: | 3/22/2000 |
| Contact: | Matt Rabe, 503-808-4510 |
Portland, Ore. – The U.S. Army Corps of Engineers is proceeding with its goal to prevent Caspian tern nesting on three Columbia River estuary islands this spring.
Portland District Engineer Col. Randall J. Butler signed a finding of no significant impact last week after reviewing the Corps' final environmental assessment of the impacts of moving the birds from Rice and Pillar Rock islands and Miller Sands Spit. The plan is to relocate the birds to East Sand Island, near the mouth of the Columbia River, and other suitable locations.
By moving the predatory birds, the Corps hopes to further help in the recovery of threatened and endangered Columbia River salmon stocks. Prevention of tern nesting on Rice Island is a requirement of the 1999 National Marine Fisheries Service biological opinion for the Corps’ Columbia River Channel Operation and Maintenance Program.
In January, the Corps issued a draft environmental assessment outlining the options determined most effective by the multi-agency Caspian Tern Working Group. The assessment was revised after the 30-day public comment period, during which time Grays Harbor in southwestern Washington became unavailable as a possible managed-relocation site for the terns for 2000.
As part of the management plan approved by the working group, about four acres of suitable habitat will be prepared for the terns on East Sand Island, a relocation site used by the Corps in 1999. Last year, about 1,400 pairs of terns moved from Rice Island to East Sand Island in a pilot study to determine if terns could be relocated. The East Sand Island site can accommodate 80 percent to 100 percent of the entire Rice Island tern colony, depending on nesting density.
Beginning about April 11, the Corps' contractor will begin active harassment of terns at the three islands in an effort to discourage nesting at those sites. The contractor will use non-lethal means to stop the birds from taking up residence on the islands. In addition, silt fencing may be built to further discourage the birds.
"We want to make conditions uncomfortable for terns on Rice Island without hurting them," said Bob Willis, the Corps' senior biologist on the CTWG. "We feel having a human presence on the island should be enough to discourage them from nesting there."
In addition to relocating Caspian terns, the Corps will add features to 12 pile dikes in the Columbia River estuary to keep double-crested cormorants, which also prey on juvenile salmon, from perching on up to 9,590 lineal feet of pile dikes and 3,836 pilings.
Caspian tern breeding was first documented in the Columbia River estuary in 1984 when about 1,000 pairs were reported nesting on fresh dredged material on East Sand Island, near the mouth of the Columbia River. Prior to 1984, the species was a non-breeding, summer resident of the Columbia River estuary.
Most of the East Sand Island colony moved to Rice Island in 1986, probably because of vegetation growth on East Sand Island, according to biologists. Since that time, the colony’s population has expanded to more than 9,500 nesting pairs. Returns of banded birds indicate that a significant proportion of the Rice Island tern colony originated from colonies in Grays Harbor and Willapa Bay, also in southwestern Washington.
Juvenile salmon and steelhead make up a large portion of the fish terns consume at Rice Island – about 75 percent, compared to a much smaller percentage at East Sand Island – about 44 percent. Biologists estimate terns, cormorants and other sea birds consumed 10.9 million, or about 11 percent, of the 95 million out-migrating salmon and steelhead that reached the Columbia River estuary in 1998.
The Caspian Tern Working Group is made up of representatives from the Corps, NMFS, Bonneville Power Administration, U.S. Fish and Wildlife, U.S.D.A. Wildlife Services, Northwest Power Planning Council, Oregon Department of Fish and Wildlife, Idaho Department of Fish and Game, Washington Department of Fish and Wildlife, Washington Department of Natural Resources, Oregon State University and the Columbia River Inter-Tribal Fish Commission.
While the CTWG provided, and will continue to provide, input, specific actions were decided by the Corps and NMFS.