• Managing avian predation in the estuary and inland Columbia

    Caspian terns and double-crested cormorants are a growing threat to juvenile chinook and steelhead in the Columbia River estuary,consuming an estimated 24.6 million juvenile Chinook and steelhead that reached the estuary in 2010.

     Caspian terns nest primarily on East Sand Island.  Since 2009, the Corps has built four alternative nesting sites to help lure the birds out of the estuary.  As a result, the Corps has been able to reduce the size of the nesting acreage on East Sand Island.

     Cormorants are a more recent threat.  In 1989, the cormorant nesting population on East Sand Island totaled only about 100 pairs.  By 2010, there were 13,596 breeding pairs on the Island – the largest double-crested cormorant colony in western North America. 

     Caspian terns and double-crested cormorants also nest on islands in the mid-Columbia River, where they also prey on juvenile salmon and steelhead. Find out more here. Key nesting sites in the mid-Columbia are Crescent Island in the McNary Pool, Goose Island in Potholes Reservoir and Foundation Island at the north end of Potholes Reservoir.  (See map.) 

     Avian predation wires installed at dams are an effective deterrent to gulls and other birds that hunt near the tailraces of dams to prey on the juveniles as they pass.  Wires installed at John Day Dam in 2010 reduced gull predation by an estimated 76 percent.  

    51_Cormorant Landings-10

    Cormorants, shown here at a bollard near Astoria, Oregon, prey on juvenile salmon in the Columbia River estuary. 

    Photo by Tony Grover, Northwest Power and Conservation Council.


  • USFWS issues depredation permit

    May 12, 2015: A federal judge has blocked a request for injunction on the federal agencies' plans under a recent EIS for lethal take of double-crested cormorants preying on juvenile salmon in the estuary. See more here.

    April 17, 2015: U.S. Fish and Wildlife Service has issued a one-year permit that will allow the U.S. Army Corps of Engineers to significantly cull the East Sand Island population of double-crested cormorants. The Corps' EIS, linked below, identified this option in order to reduce the birds’ predation on juvenile salmon.

    Read more about the story here.

    February 6, 2015: Corps releases EIS on Double-crested Cormorant Management Plan to Reduce Predation of Juvenile Salmonids in the Columbia River Estuary. Read more about the study on the Corps Website.

    Ongoing research on Columbia Basin bird colonies
    Bird Research Northwest (formerly Columbia Bird Research) is an ongoing research program investigating the ecology of fish-eating waterbird colonies (primarily, Caspian terns, double-crested cormorants, American white pelicans, and several gull species) and their impacts on the survival of juvenile salmonids in the Columbia Basin and elsewhere along the Pacific Coast. Visit the website.
    Inland avian predation
    The Corps and Reclamation are implementing the first phase of a five-year plan to manage tern predation in the Columbia Basin. Read more here.