The mission of the US Fish and Wildlife Service is working with others to conserve, protect, and enhance fish, wildlife, and plants and their habitats for the continuing benefit of the American people. U.S. Fish and Wildlife Service - Pacific Region
Migratory Birds and Habitat Programs

Caspian Tern Management in the Columbia River Estuary

Caspian Tern flying with a smolt in its bill

Background

Since 1995, the National Marine Fisheries Service (NOAA Fisheries) has been concerned about Caspian tern predation on threatened or endangered salmon in the Columbia River estuary (see map below). Research indicated that Caspian terns nesting on Rice Island consumed more young salmonids (smolts) than any other type of fish. In 1999, NOAA Fisheries called for the U.S. Army Corps of Engineers (Corps) to eliminate tern nesting from Rice Island (located in the upper estuary) in an attempt to decrease the number of juvenile salmonids eaten by terns. In 1999, the Corps initiated a pilot project to relocate the Rice Island tern colony to East Sand Island, near the mouth of the estuary where marine fish (i.e., non-salmon) were abundantly available to foraging terns (U.S. Army Corps of Engineers 1999b). In 2000, the Corps proposed to complete the relocation effort to prevent all tern nesting on Rice Island while attracting terns to nest on East Sand Island.
As a result of the proposed actions in 2000, Seattle Audubon, National Audubon, American Bird Conservancy, and Defenders of Wildlife filed a lawsuit against the Corps and U.S. Fish and Wildlife Service (USFWS). The four groups alleged in the suit that compliance with the National Environmental Policy Act (NEPA) was not sufficient for the proposed action of relocating Caspian terns from Rice Island to East Sand Island. Furthermore, the groups objected to the Service's issuance of a Migratory Bird Treaty Act (MBTA) permit authorizing the potential take of tern eggs as a means to prevent tern nesting on Rice Island.
In 2002, all parties reached a Settlement Agreement. Terms of the agreement required the Service (lead agency), Corps, and NOAA Fisheries to prepare an Environmental Impact Statement to address long-term management of Caspian terns in the Columbia River estuary. The 2002 Settlement Agreement also required the Service and NOAA Fisheries to develop and publish three technical reports: (1) Status Assessment and Conservation Recommendations for the Caspian Tern in North America, (2) Caspian Tern Predation on Salmon and Steelhead Smolts in the Columbia River Estuary, and (3) A Review of Caspian Tern Nesting Habitat: A Feasibility Assessment of Management Opportunities in the U.S. Fish and Wildlife Service Pacific Region. These reports are available below.
Although the relocation of terns from Rice Island to East Sand Island resulted in a decreased percentage of salmonids in the tern diet, NOAA Fisheries continues to be concerned about tern predation on juvenile salmonids because of a projected increase in the tern colony size on East Sand Island.

 

Columbia River Estuary

Map of Columbia River Estuary